JPH04335968A - Apparatus for air conditioning - Google Patents

Abstract

PURPOSE:To reduce the noise of flowing refrigerant at the transitional stage of the start-up, by a method wherein, after the start, the third flow-rate controlling device is controlled in such a manner as not to allow its opening to exceed a certain degree before the subcooling at the inlet to the third flow-rate controlling device, whose value is calculated from a detected pressure and a detected temperature, reaches a specified value. CONSTITUTION:A system has, between a heat-source unit A and a plurality of indoor units B, C, and D, a relay unit E which contains a first branching part 10, a second branching part 11, the second flow-rate controlling device 13, the third flow-rate controlling device 15, the second pressure-detecting means 26, and a temperature-detecting means 27. After the start of the compressor 1 in this system, the third flow-rate controlling device 15 is controlled in such a manner as not to allow its opening to exceed a certain degree before the subcooling at the inlet to the third flow-rate controlling device 15, whose value is calculated from the pressure detected by the second pressure-detecting means 26 and the temperature detected by the temperature-detecting means 27, reaches a preliminarily set value.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This 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 also relates to an air conditioner that can simultaneously perform cooling with one indoor unit and heating with the other indoor unit.

0002

[Prior Art] Conventionally, a heat pump type air conditioner is common, in which multiple indoor units are connected to one heat source unit through two pipes, a gas pipe and a liquid pipe, to perform heating and cooling operation. The machines are configured for either all heating or all cooling.

0003

[Problems to be Solved by the Invention] Since the conventional multi-room heat pump type air conditioner is configured as described above, all indoor units operate only for cooling or heating, so heating is performed only in places where cooling is required. There were problems such as air conditioning being used in places that needed heating, or cooling being used in places that needed heating. especially,
When installed in a large building, the air conditioning load will be significantly different between the interior and perimeter areas, or between general offices and computer rooms and other open air rooms.
This is a particular problem. Note that as an approximation technique, there is Japanese Patent Application Laid-Open No. 1-134172.

[0004] This invention was made to solve the above-mentioned problems, and it connects a plurality of indoor units to one heat source unit, and selectively controls heating and cooling for each indoor unit. In addition, if one indoor unit can perform cooling and the other indoor unit can perform heating at the same time and is installed in a large building, it will be possible to open the interior and perimeter areas, general offices, computer rooms, etc. To provide a multi-room heat pump type air conditioner that can handle each room even if the air conditioning load differs significantly between rooms. Another purpose is to reduce refrigerant flow noise during transient periods.

[0005]

[Means for Solving the Problems] An air conditioner according to the present invention includes one heat source machine consisting of a compressor, a four-way valve, a heat exchanger on the heat source machine side, and an accumulator, an indoor heat exchanger,
a plurality of indoor units consisting of a first flow rate control device;
, a valve device connected via a second connection pipe to switchably connect one of the indoor heat exchangers of the plurality of indoor units to the first connection pipe or the second connection pipe. 1st
and the other of the indoor heat exchangers of the plurality of indoor units via the first flow rate control device, and a second
and a second branch section connected to the second connecting pipe via the flow rate control device, one end of which is connected to the second branch section, and the other end is connected to the second branch section via the second flow rate control device. A bypass pipe whose end is connected to the first connection pipe via a third flow rate control device is provided, and a second pressure detection means is provided between the second flow rate control device and the third flow rate control device. Temperature detection means is provided, and the first branch section, the second branch section, the second flow rate control device, the third flow rate control device, and the second branch section are provided.
A repeater having built-in pressure detecting means and temperature detecting means is interposed between the heat source device and the plurality of indoor units, wherein after the compressor is started, the second pressure detecting means is installed. Until the subcool at the inlet of the third flow rate control device, which is calculated from the detected pressure of the means and the temperature detected by the temperature detection means, reaches a preset value, the opening degree of the third flow rate control device is controlled. A transient flow rate control device control means is provided for controlling the third flow rate control device so that the opening degree does not exceed a certain certain level.

[0006] Also, after the defrosting operation is completed and each indoor unit is operated only for heating, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source side is switched to operation as an evaporator. , until the subcool at the inlet of the third flow rate control device calculated from the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means reaches a preset value. Transient flow rate control device control means is provided for controlling the third flow rate control device so that the opening degree of the third flow rate control device does not exceed a certain degree of opening.

[0007] In addition, each indoor unit is operated only for cooling, or each indoor unit is simultaneously operated for cooling and heating, and the heat exchanger on the heat source equipment side functions as a condenser, and each indoor unit is operated only for heating, or After each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source side is switched to operation as an evaporator,
Until the subcool at the inlet of the third flow rate control device, which is calculated from the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means, reaches a preset value, the third Transient flow rate control device control means is provided for controlling the third flow rate control device so that the opening degree of the flow rate control device does not exceed a certain opening degree.

[0008] In addition, each indoor unit can be operated only for heating, or each indoor unit can be operated simultaneously for cooling and heating, and the heat exchanger on the heat source side functions as an evaporator, or each indoor unit can be operated only for cooling, or After each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source side is switched to operation as an evaporator,
Until the subcool at the inlet of the third flow rate control device, which is calculated from the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means, reaches a preset value, the third Transient flow rate control device control means is provided for controlling the third flow rate control device so that the opening degree of the flow rate control device does not exceed a certain opening degree.

[0009]

[Operation] In the present invention, during a transient period after starting the compressor, the high pressure has not risen sufficiently, so the refrigerant at the inlet of the third flow rate control device is not in a supercooled liquid state but in a flash state; Until the subcooling reaches a preset value, the opening of the third flow rate control device is prevented from exceeding a certain degree, thereby suppressing the sound of the refrigerant flowing through the third flow rate control device. .

Furthermore, during defrosting operation, the high pressure is low and the liquid refrigerant in the intermediate pressure section between the second flow control device and the third flow control device leaks into the low pressure section. At the time of transition after the completion of the operation and each indoor unit is operated only for heating, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source equipment side is switched to operation in which the heat exchanger on the heat source side functions as an evaporator, the third
The refrigerant at the inlet of the third flow rate control device is not a supercooled liquid but is in a flash state, and the opening of the third flow rate control device remains constant until the subcool reaches a preset value. The noise of the refrigerant flowing through the third flow rate control device is suppressed to a low level by not exceeding the opening degree.

[0011] In addition, each indoor unit is operated only for cooling, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source equipment side functions as a condenser, and each indoor unit is operated only for heating, or During a transition period after each indoor unit is operated simultaneously for cooling and heating and the heat exchanger on the heat source side is switched to operation as an evaporator, the four-way valve is switched and the high pressure and intermediate pressure are temporarily lowered. Since the liquid refrigerant in the intermediate pressure section evaporates and leaks into the low pressure section, the refrigerant at the inlet of the third flow rate control device is not in a supercooled liquid state but in a flash state, and subcooling is preset. Until the value is reached,
The opening degree of the third flow rate control device is prevented from exceeding a certain degree of opening, thereby suppressing the noise of refrigerant flowing through the third flow rate control device.

[0012] In addition, each indoor unit can be operated only for heating, or each indoor unit can be operated simultaneously for cooling and heating, and the heat exchanger on the heat source side functions as an evaporator, or each indoor unit can be operated only for cooling, or At the time of transition after each indoor unit is operated simultaneously for cooling and heating and the heat exchanger on the heat source side is switched to operation as a condenser, the superheated gas refrigerant filling the second connection pipe before switching is Since the refrigerant is supplied to the repeater, the refrigerant at the inlet of the third flow rate control device is not a supercooled liquid but is in a flash state, and the opening of the third flow rate control device is above a certain opening degree. The noise of the refrigerant flowing through the third flow rate control device is suppressed to a low level.

[0013]

[Example] Example 1. Examples of the present invention will be described below. FIG. 1 is an overall configuration diagram centered on the refrigerant system of an air conditioner according to an embodiment of the present invention. 2 to 4 show operating states during cooling/heating operation in one embodiment of Fig. 1. Fig. 2 is an operating state diagram for cooling or heating only, and Figs. 3 and 4 are for simultaneous cooling/heating operation. It shows the operation,
Figure 3 is a diagram showing the operating state of heating-dominant operation (when the heating operating capacity is larger than the cooling operating capacity), Figure 4 is the operating state diagram showing cooling-dominant operation (when the cooling operating capacity is larger than the heating operating capacity), and Figure 5 is a diagram of the defrosting operation. FIG. FIG. 8 is an overall configuration diagram centered on the refrigerant system of an air conditioner according to another embodiment of the present invention. In this embodiment, a case will be described in which three indoor units are connected to one heat source device, but the same applies to a case in which two or more indoor units are connected. In FIG. 1, A is a heat source device, and B, C, and D are indoor units connected in parallel to each other, each having the same configuration as described later. E
As will be described later, the device has a built-in first branching section, a second flow rate control device, a second branching section, a gas-liquid separation device, a heat exchange section, a third flow rate control device, and a fourth flow rate control device. It is a repeater. 1 is a compressor, 2 is a heat source device that switches the refrigerant flow direction 4
3 is a heat exchanger on the heat source machine side, and 4 is an accumulator, to which the above-mentioned devices are connected, and the heat source machine A is configured by these. 5 is the indoor heat exchanger installed in the three indoor units B, C, and D; 6 is the thick first connection pipe that connects the four-way valve 2 of the heat source device A and the repeater E; 6b, 6c, 6d is the first connection pipe on the indoor unit side that connects the indoor heat exchanger 5 of the indoor units B, C, and D and the repeater E, and corresponds to the first connection pipe 6, and 7 is the first connection pipe of the heat source unit A. Heat source machine side heat exchanger 3 and repeater E
Second connection pipes 7b, 7c, and 7d, which are thinner than the first connection pipes, connect the indoor heat exchangers 5 of the indoor units B, C, and D and the repeater E to the first flow rate control device 9, respectively. A second connection pipe 8 on the indoor unit side that is connected to the second connection pipe 7 and corresponds to the second connection pipe 7, 8 is the first connection pipe 6b, 6c,
6d, and the first connection pipe 6 which is switchably connected to the first connection pipe 6 or the second connection pipe 7 side and which is on the indoor unit side.
b, 6c, 6d, first connection pipe 6, second connection pipe 7
A three-way switching valve that can close the flow with any of the following.
Reference numeral 9 denotes a first flow rate control device that is connected close to the indoor heat exchanger 5 and is controlled by the amount of superheat on the outlet side of the indoor heat exchanger 5 during cooling and the amount of subcooling during heating; It is connected to the second side connection pipes 7b, 7c, and 7d. Reference numeral 10 denotes a first branch part consisting of a three-way switching valve 8 that is switchably connected to the first connection pipes 6b, 6c, and 6d on the indoor unit side, and the first connection pipe 6 or the second connection pipe 7; 11
12 is a gas-liquid separation device provided in the middle of the second connection pipe 7; The gas layer portion is connected to the first port 8a of the three-way switching valve 8, and the liquid layer portion is connected to the second branch portion 11. 13 is a second flow rate control device (here, an electric expansion valve) that can be opened and closed and is connected between the gas-liquid separation device 12 and the second branch 11; A bypass pipe 15 connects the connecting pipe 6 of No. 1, and 15 is a third flow rate control device (here, an electric expansion valve) provided in the middle of the bypass pipe 14, 16a.
is provided downstream of the third flow rate control device 15 provided in the middle of the bypass pipe 14, and is connected to the meeting part of the second connection pipes 7b, 7c, 7d on each indoor unit side in the second branch part 11. a second heat exchange section, 16b, which performs heat exchange between the two;
, 16c, and 16d are each provided downstream of the third flow rate control device 15 provided in the middle of the bypass piping 14,
A third heat exchange section 19 that performs heat exchange with the second connection pipes 7b, 7c, and 7d on each indoor unit side in the second branch section 11 is configured to adjust the third flow rate of the bypass pipe 14. A first heat exchange section that exchanges heat between piping that is provided downstream of the control device 15 and downstream of the second heat exchange section 16a and connects the gas-liquid separation device 12 and the second flow rate control device 13. ,
17 is a fourth openable/closeable flow rate control device (here, an electric expansion valve) connected between the second branch portion 11 and the first connection pipe 6, and 32 is the heat exchanger on the heat source machine side. 3 and the second connection pipe 7, and is a third check valve provided between the heat source equipment side heat exchanger 3 and the second connection pipe 7.
Allow refrigerant flow only to 33 is 4 of the above heat source machine A
A fourth pipe provided between the direction valve 2 and the first connection pipe 6
This check valve allows refrigerant to flow only from the first connecting pipe 6 to the four-way valve 2. 34 is a fifth check valve provided between the four-way valve 2 of the heat source device A and the second connecting pipe 7; Only allow refrigerant flow. 35 is a sixth check valve provided between the heat source machine side heat exchanger 3 and the first connection pipe 6, and 35 is a sixth check valve provided between the heat source machine side heat exchanger 3 and the first connection pipe 6; Refrigerant flow is allowed only to 3. 3rd above
, fourth, fifth, and sixth check valves 32, 33, 34, and 35 constitute a switching valve 40. 49 is the heat source machine side switching valve 40
and the second connection pipe 7 and the heat source machine side switching valve 4.
0 and the first connecting pipe 6; 48 is a sixth heat source machine side bypass passage provided in the middle of the heat source machine side bypass passage 49 to control opening/closing of the heat source machine side bypass passage 49; 25 is a first pressure detection means provided between the first branch 10 and the second flow rate control device 13; 26 is a first pressure detection means provided between the second flow rate control device 13 and the third flow rate control device 13; A second pressure detection means 27 is provided between the control device 15 and the third flow rate control device 15, and a temperature detection device 27 is provided at the inlet portion of the third flow rate control device 15.

An embodiment of the invention configured as described above will be explained. First, the case of only cooling operation will be described using FIG. 2. That is, as shown by the solid arrow in the figure, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, exchanges heat with air in the heat exchanger 3 on the heat source equipment side, and is condensed and liquefied. Third check valve 32, second connection pipe 7
, the gas-liquid separator 12, and the second flow rate control device 13, and further passes through the second branch 11 and the second connection pipes 7b, 7c, and 7d on the indoor unit side, to each indoor unit B, C, Flows into D. The refrigerant flowing into each of the indoor units B, C, and D is then reduced to a low pressure by the first flow control device 9, which is controlled by the amount of superheat at the outlet of each indoor heat exchanger 5, and then transferred to the indoor heat exchanger 5. 5, it exchanges heat with indoor air and evaporates into gas, cooling the room. Then, the refrigerant in the gas state is transferred to the first connecting pipes 6b, 6c, 6d on the indoor unit side, the three-way switching valve 8, the first branch part 10, the first connecting pipe 6, and the fourth check valve. Valve 33, heat source machine 4-way valve 2, accumulator 4
The air is sucked into the compressor 1 through a circulation cycle to perform cooling operation. At this time, the first port 8a of the three-way switching valve 8
is closed, and the second port 8b and third port 8c are open. At this time, since the first connecting pipe 6 is under low pressure and the second connecting pipe 7 is under high pressure, the third check valve 32 and the fourth check valve 3 are inevitably closed.
Distribution to 3. Also, during 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.
The heat exchange parts 16b, 16c, 16d of the second branch part 11
The second connection pipes 7b, 7c, 7d on each indoor unit side of the second branch part 11 in the second heat exchange section 16a 7d and the second flow rate control device 13 at the first heat exchange section 19.
The refrigerant that evaporated through heat exchange with the refrigerant flowing into the
4 of the heat source device enters the first connection pipe 6 and the fourth check valve 33.
The air is sucked into the compressor 1 through the direction valve 2 and the accumulator 4. On the other hand, the first, second and third heat exchange parts 19, 16a, 1
The refrigerant in the second branch section 11, which has been cooled by heat exchange in 6b, 16c, and 16d and has been sufficiently subcooled, flows into the indoor units B, C, and D that are to be cooled.

Next, the case of only heating operation will be explained using FIG. That is, as shown by the 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 first connection pipe 7, and the gas-liquid separation device. 12, the first branch 10, the three-way switching valve 8
, first connection pipes 6b, 6c, and 6d on the indoor unit side, flow into each indoor unit B, C, and D, exchange heat with indoor air, condense and liquefy, and heat the room. The refrigerant in the liquid state is controlled by the sub-cooling amount at the outlet of each indoor heat exchanger 5, and the first flow rate control device 9 is in a substantially fully open state.
, flows into the second branch part 11 from the second connection pipes 7b, 7c, and 7d on the indoor unit side, joins together, and further passes through the fourth flow rate control device 17. Here, the first flow rate control device 9,
Alternatively, the pressure is reduced to a low pressure gas-liquid two-phase state by either the third or fourth flow rate control device 13 or 17. The refrigerant, which has been reduced in pressure to a low pressure, flows through the first connection pipe 6 to the sixth check valve 35 of the heat source device A and the heat exchanger 3 on the heat source device side, where it exchanges heat with air and evaporates. The refrigerant in the gas state is
A circulation cycle is configured in which air is sucked into the compressor 1 through the four-way valve 2 of the heat source device and the accumulator 4, and heating operation is performed. At this time, the second port 8b of the three-way switching valve 8 is closed, and the first port 8a and third port 8c are opened. Also, 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 is inevitably passed through the fifth check valve 34 and the sixth check valve 35.
distributed to.

[0016] A case in which heating is the main component in simultaneous cooling and heating operation will be explained with reference to FIG. That is, as shown by the dotted line arrow in the same figure, the high temperature and high pressure refrigerant gas discharged from the compressor 1 is sent to the repeater E through the fifth check valve 34 and the second connection pipe 7, and then connected to the gas-liquid separation device. 12, and in this order the first branch part 10, the three-way switching valve 8, and the first connection pipes 6b and 6c on the indoor unit side, to each indoor unit B to be heated.
C, and exchanges heat with indoor air in the indoor heat exchanger 5 to be condensed and liquefied to heat the room. This condensed and liquefied refrigerant is controlled by the subcooling amount at the outlet of each of the indoor heat exchangers B and C, passes through the first flow rate control device 9 that is almost fully open, and is slightly depressurized before flowing into the second branch section 11. do. A part of this refrigerant is then transferred to the second connection pipe 7d on the indoor unit side.
, enters the indoor unit D to be cooled, enters the first flow rate control device 9 controlled by the amount of superheat at the outlet of the indoor heat exchanger D, and is depressurized, then enters the indoor heat exchanger 5
The gas exchanges heat with the air, evaporates, becomes a gas, cools the room, and flows into the first connection pipe 6 via the three-way switching valve 8. On the other hand, other refrigerants pass through a fourth flow rate control device 17 that is controlled so that the pressure difference between the pressure detected by the first pressure detection means 25 and the pressure detected by the second pressure detection means 26 is within a predetermined range. , joins with the refrigerant that has passed through the indoor unit D to be cooled, flows through the thick first connection pipe 6, into the sixth check valve 35 of the heat source unit A, and into the heat exchanger 3 on the heat source unit side, where the air It exchanges heat with and evaporates, becoming a gas. Then, the refrigerant forms a circulation cycle in which the refrigerant is sucked into the compressor 1 through the four-way valve 2 of the heat source device and the accumulator 4, thereby performing heating-dominant operation. At this time, the pressure difference between the evaporation pressure of the indoor heat exchanger 5 of the indoor unit D to be cooled and the pressure of the heat source device side heat exchanger 3 becomes small because the first connection pipe 6 is switched to the thick one. Also, at this time, the second port 8b of the three-way switching valve 8 connected to the indoor units B and C is closed, the first port 8a and the third port 8c are open, and the first port 8a of the indoor unit D is closed. The circuit is closed, and the second port 8b and third port 8c are open. Further, at this time, the refrigerant inevitably flows to the fifth check valve 34 and the sixth check valve 35 because the first connection pipe 6 is under low pressure and the second connection pipe 7 is under high pressure. Also, during this cycle, a part of the liquid refrigerant enters the bypass pipe 14 from the meeting part of the second connection pipes 7b, 7c, and 7d on each indoor unit side of the second branch part 11 and enters the third flow rate control device. The pressure is reduced to low pressure at step 15, and the second connection pipe 7b on each indoor unit side of the second branch section 11 is connected to the third heat exchange section 16b, 16c, 16d.
7c, 7d, the second connection pipes 7b, 7c, 7 on each indoor unit side of the second branch part 11 in the second heat exchange part 16a.
The refrigerant that evaporated after exchanging heat with the meeting part of d is
The water enters the connecting pipe 6 and the sixth check valve 35, passes through the four-way valve 2 of the heat source device, and the accumulator 4, and is sucked into the compressor 1. On the other hand, the second and third heat exchange parts 16a, 16b, 16c, 1
The refrigerant in the second branch part 11, which has been cooled by heat exchange in step 6d and has been sufficiently subcooled, flows into the indoor unit D which is to be cooled.

[0017] A case in which air conditioning is mainly used for heating and air conditioning at the same time will be explained with reference to FIG. That is, as shown by the solid line arrow in the figure, the refrigerant gas discharged from the compressor 1 flows into the heat exchanger 3 on the heat source side, where it exchanges heat with the air and becomes a high temperature and high pressure state of gas-liquid two-phase. . After that, this two-phase high temperature and high pressure refrigerant passes through the third check valve 32 and the second connection pipe 7.
It is sent to the gas-liquid separator 12 of the repeater E. Here, the gaseous refrigerant is separated into a gaseous refrigerant and a liquid refrigerant, and the separated gaseous refrigerant is passed through the first branch part 10, the three-way switching valve 8, and the first connecting pipe 6d on the indoor unit side in this order to perform heating. It flows into the indoor unit D, exchanges heat with indoor air in the indoor heat exchanger 5, condenses and liquefies, and heats the room. Furthermore, it is controlled by the subcooling amount at the outlet of the indoor heat exchanger 5, and passes through the first flow rate control device 9, which is in an almost fully open state, and is slightly depressurized before flowing into the second branch section 11. On the other hand, the remaining liquid refrigerant flows into the second branch section 11 through the second flow control device 13 controlled by the pressure detected by the first pressure detection means 25 and the pressure detected by the second pressure detection means 26. Then, it merges with the refrigerant that has passed through the indoor unit D to be heated. And the second branch part 11
, the second connection pipes 7b and 7c on the indoor unit side in that order, and flow into each of the indoor units B and C. The refrigerant that has flowed into each of the indoor units B and C is then reduced to a low pressure by the first flow rate control device 9, which is 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 and becomes gas, cooling the room. Furthermore, this refrigerant in a gas state is transferred to the first connection pipes 6b, 6c and the three-way switching valve 8 on the indoor unit side.
, constitutes a circulation cycle in which the water passes through the first branch part 10, passes through the first connection pipe 6, the fourth check valve 33, the four-way valve 2 of the heat source device, and the accumulator 4, and is sucked into the compressor 1, Performs cooling-based operation. Also, at this time, the first port 8a of the three-way switching valve 8 connected to the indoor units B and C is closed, the second port 8b and the third port 8c are open, and the second port 8b of the indoor unit D is closed. The circuit is closed, and the first port 8a and the third port 8c are open. Further, at this time, the refrigerant inevitably flows to the third check valve 32 and the fourth check valve 33 because the first connection pipe 6 is under low pressure and the second connection pipe 7 is under high pressure. Also, during this cycle, a part of the liquid refrigerant enters the bypass pipe 14 from the meeting part of the second connection pipes 7b, 7c, and 7d on each indoor unit side of the second branch part 11 and enters the third flow rate control device. 15, the pressure is reduced to low pressure and the third
The heat exchange parts 16b, 16c, 16d of the second branch part 11
The second connection pipes 7b, 7c, 7d on each indoor unit side of the second branch part 11 in the second heat exchange section 16a 7d and the second flow rate control device 13 at the first heat exchange section 19.
The refrigerant that evaporated through heat exchange with the refrigerant flowing into the
4 of the heat source device enters the first connection pipe 6 and the fourth check valve 33.
The air is sucked into the compressor 1 through the direction valve 2 and the accumulator 4. On the other hand, the first, second and third heat exchange parts 19, 16a, 1
The refrigerant in the second branch section 11, which has been cooled by heat exchange in 6b, 16c, and 16d and has been sufficiently subcooled, flows into the indoor units B and C that are to be cooled.

Next, the case of defrosting operation will be explained using FIG. 5. Since the sixth electromagnetic on-off valve 48 and the second and third flow rate control devices 13 and 15 are open, immediately after the start of the defrosting operation, the second connection pipe 7 is opened as shown by the broken line arrow in the figure.
Most of the high-temperature, high-pressure gas refrigerant that had filled the air flowed through the heat source machine side bypass passage 49 to the low-pressure side, and then passed through the fourth check valve 3.
3, flows into the accumulator 4 through the 4-way valve 2, and a small amount of the remainder passes through the gas-liquid separator 12, the second and third flow control devices 13, 15, is reduced to low pressure, and is transferred to the first connecting pipe. 6
, the fourth check valve 33, and the accumulator 4 via the four-way valve 2.
flows into. In addition, after the gas refrigerant in the second connection pipe 7 escapes to the low-pressure side, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, as shown by the solid arrow, and passes through the heat exchanger on the heat source equipment side. After the refrigerant is condensed and liquefied by exchanging heat with the frost in step 3, most of the refrigerant passes through the third check valve 32 and is reduced to a low pressure via the bypass passage 49 on the heat source machine side, and a small amount of the remaining refrigerant is transferred to the second connection. It passes through the pipe 7 and the gas-liquid separator 12 in this order, is reduced to a low pressure by the second flow control device 13 or the third flow control device 15, and flows into the heat source device via the first connection pipe 6. The refrigerant that has passed through the heat source device side bypass path 49 and the refrigerant that has passed through the repeater E merge at the inlet of the fourth check valve 33 .
, the four-way valve 2, and the accumulator 4, and then flows into the compressor 1. Since a circulation cycle is formed in this way, the heat quantity of the refrigerant filling the second connection pipe 7, the heat quantity of the second connection pipe 7, and the heat quantity of the repeater E can be collected quickly before the defrosting operation starts. It is possible to reliably melt the frost formed on the heat exchanger 3 on the heat source machine side. Immediately after the start of the defrosting operation, most of the high-temperature, high-pressure gas refrigerant that filled the second connection pipe 7 flows to the low-pressure side through the heat source device side bypass passage 49, and the second and third flow rate controls are performed. Since the amount of refrigerant passing through the devices 13 and 15 is small, high temperature and high pressure gas refrigerant is passed through the second and third flow rate control devices 13 and 1.
The sound that passes through 5 is small. Also, the heat source machine side heat exchanger 3
Most of the refrigerant condensed and liquefied by exchanging heat with the frost is reduced to a low pressure through the heat source machine side bypass passage 49, and is therefore reduced to a low pressure by the second flow rate control device 13 or the third flow rate control device 15. The amount of refrigerant flowing into the second and third flow control devices 13 and 15 is sufficiently cooled in the first and second heat exchange parts 19 and 16a and becomes liquid refrigerant. The refrigerant noise passing through the third flow rate control devices 13 and 15 is small.

Next, the control contents of the third flow rate control device 15 during a transient period after the compressor 1 is started will be explained. Compressor 1
During the transition period after startup, the high pressure has not risen sufficiently, so the refrigerant at the inlet of the third flow rate control device 15 is not in a supercooled liquid state and is in a flash state, and the third flow rate control device 15 is not opened. When the degree of opening exceeds a certain level, the sound of the refrigerant flowing through the third flow rate control device 15 becomes louder. Therefore, in order to suppress the flow noise, the third flow rate control device 15 is controlled as described below. Figure 6 shows the third
FIG. 2 is a block diagram showing control details of the flow rate control device 15 of FIG. 41 is a transient flow rate control device control means. FIG. 7 is a flowchart showing the operation of the third flow rate control device 15 during a transient period. In step 50, the second pressure detection means 26
The subcool SC of the inlet portion of the third flow rate control device 15 is calculated from the detected pressure and the detected temperature of the temperature detection means 27. Next, it is determined whether the subcool SC calculated in step 51 is larger than a preset value SC0. If SC≧SC0, the opening degree S of the third inflow control device 15 is controlled so that the degree of superheat of the refrigerant inflow pipe portion 14a from the bypass circuit 14 to the first connection pipe 6 becomes a predetermined value. If SC<SC0, the process proceeds to step 52, where it is determined whether the opening degree S of the third flow rate control device 15 is larger than a certain opening degree S0, and if SC≦S0, the process returns to step 50. . On the other hand, if S>S0, S
=S0 and return to step 50. In this way, when the refrigerant is in a flash state at the inlet of the third flow rate control device 15, the opening degree is restricted to reduce the refrigerant flow noise, and sufficient subcooling is obtained at the inlet of the third flow rate control device 15, so that the refrigerant Since the restriction on the opening degree is lifted after the flow noise becomes low, noise can be reduced.

Example 2. Next, the transient state after the defrosting operation is finished and each indoor unit is operated only for heating, or each indoor unit is simultaneously operated for cooling and heating, and the heat exchanger 3 on the heat source side is switched to operation as an evaporator. The control contents of the third flow rate control device 15 at this time will be explained. During defrosting operation, the high pressure is low;
Since the liquid refrigerant in the intermediate pressure section between the second flow control device 13 and the third flow control device 15 leaks into the low pressure section,
During a transition period after the defrosting operation is completed and each indoor unit is operated only for heating, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger 3 on the heat source side is switched to operation as an evaporator,
The refrigerant at the inlet of the third flow rate control device 15 is not a supercooled liquid but is in a flash state, and when the opening of the third flow rate control device 15 reaches a certain opening degree or more, the third flow rate control device The flow noise of the refrigerant passing through 15 becomes louder. Therefore, in order to suppress the flow noise to a low level, a third flow rate control device 15 is installed.
When the refrigerant is in a flash state at the inlet of the third flow rate control device 15, the opening degree is restricted, and the restriction on the opening degree is canceled after sufficient subcooling is obtained at the inlet of the third flow rate control device 15 and the refrigerant flow noise becomes small. The specific control content of the third flow rate control device 15 is the same as that during the transient period after the compressor 1 is started, so a description thereof will be omitted here.

Example 3. Next, each indoor unit is operated only for cooling, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger 3 on the heat source equipment side functions as a condenser, and then each indoor unit is operated only for heating, or each indoor unit is operated for heating only, or The control contents of the third flow rate control device 15 during a transient period after switching to operation in which the heat source machine side heat exchanger 3 functions as an evaporator when the machine is simultaneously cooled and heated will be explained. Each indoor unit is operated only for cooling, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger 3 on the heat source side functions as a condenser. At the time of simultaneous operation and a transition after switching to operation in which the heat source machine side heat exchanger 3 functions as an evaporator,
The four-way valve 2 is switched, the high pressure and intermediate pressure are temporarily lowered, and the liquid refrigerant in the intermediate pressure part evaporates and leaks into the low pressure part, so the refrigerant at the inlet of the third flow rate control device 15 is overflowed. It is not a coolant and is in a flash state, and when the opening of the third flow control device 15 exceeds a certain opening, the third
The sound of the refrigerant flowing through the flow rate control device 15 becomes louder. Therefore, in order to suppress the flow noise, the opening degree is limited when the refrigerant is in a flash state at the inlet of the third flow rate control device 15, so that sufficient subcooling is obtained at the inlet of the third flow rate control device 15, and the refrigerant flows. Release the opening limit after the sound becomes quiet. The specific control content of the third flow rate control device 15 is the same as that during the transient period after the compressor 1 is started, so a description thereof will be omitted here.

Example 4. Next, each indoor unit is operated only for heating, or each indoor unit is simultaneously operated for cooling and heating, and the heat exchanger 3 on the heat source equipment side acts as an evaporator, and then each indoor unit is operated only for cooling, or each indoor unit is operated for cooling only, or each indoor unit is operated for cooling and heating at the same time. The control content of the third flow rate control device 15 during a transient period after the machine is simultaneously cooled and heated and the heat source machine side heat exchanger 3 switches to operation as a condenser will be described. Each indoor unit operates only for heating, or each indoor unit operates simultaneously for cooling and heating, and the heat exchanger on the heat source unit functions as an evaporator; each indoor unit operates only for cooling;
Or, during a transition period after each indoor unit is simultaneously cooled and heated and the heat exchanger on the heat source side is switched to the condenser 3, the superheated gas refrigerant filling the second connection pipe 7 before switching is After switching, it is supplied to repeater E, so
The refrigerant at the inlet of the third flow rate control device 15 is not a supercooled liquid but is in a flash state, and when the opening of the third flow rate control device 15 reaches a certain opening degree or more, the third flow rate control device The flow noise of the refrigerant passing through 15 becomes louder. Therefore, in order to suppress the flow noise to a low level, a third flow rate control device 15 is installed.
When the refrigerant is in a flash state at the inlet of the third flow rate control device 15, the opening degree is restricted, and the restriction on the opening degree is canceled after sufficient subcooling is obtained at the inlet of the third flow rate control device 15 and the refrigerant flow noise becomes small. The specific control content of the third flow rate control device 15 is the same as that during the transient period after the compressor 1 is started, so a description thereof will be omitted here.

Example 5. In the above embodiment, a three-way switching valve 8 is provided to connect the first connection pipes 6b, 6c, 6 on the indoor unit side.
d, and is switchably connected to the first connecting pipe 6 or the second connecting pipe 7, and as shown in FIG. Even if they are connected in a switchable manner, similar effects can be obtained.

[0024]

Effects of the Invention As explained above, the air conditioner of the present invention includes one heat source machine consisting of a compressor, a four-way valve, a heat exchanger on the heat source machine side, and an accumulator, an indoor heat exchanger, and a second heat exchanger. A plurality of indoor units comprising one flow rate control device are connected via first and second connection pipes, and one of the indoor heat exchangers of the plurality of indoor units is connected to the first connection pipe. or a first branching section equipped with a valve device that is switchably connected to the second connection pipe and connected to the other of the indoor heat exchangers of the plurality of indoor units via the first flow rate control device. and a second branch section connected to the second connection pipe via the second flow rate control device, and one end is connected to the second branch section via the second flow rate control device. and the other end is connected to the third
A bypass pipe is provided which is connected to the first connection pipe via a flow rate control device, and the second flow rate control device and the third connection pipe are connected to each other.
A second pressure detection means and a temperature detection means are provided between the flow control devices, the first branch section, the second branch section, the second flow control device, the third flow control device, A repeater incorporating the second pressure detection means and the temperature detection means is interposed between the heat source device and the plurality of indoor units, wherein the The third flow rate control device is operated until the subcool at the inlet of the third flow rate control device calculated from the detected pressure of the second pressure detection means and the detected temperature of the temperature detection device reaches a preset value. Since the transient flow rate control device control means is provided to control the third flow rate control device so that the opening does not exceed a certain opening, the high pressure does not rise sufficiently during the transition of starting the compressor. As a result, even if the refrigerant at the inlet of the third flow rate control device does not become a supercooled liquid and is in a flash state, the noise of the refrigerant flowing through the third flow rate control device can be suppressed to a low level, thereby reducing the noise of the repeater. The noise will be reduced.

[0025] Also, after the defrosting operation is completed and each indoor unit is operated only for heating, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source side is switched to operation as an evaporator. During the transient period of , the third flow control device is operated until the subcool at the inlet of the third flow rate control device, which is calculated from the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means, reaches a preset value. Since the third flow rate control device is provided with a transient flow rate control device control means for controlling the third flow rate control device so that the opening degree of the flow rate control device does not exceed a certain opening degree, the high pressure is low during the defrosting operation. Second flow control device 13
The liquid refrigerant in the intermediate pressure section between the and the third flow rate control device 15 leaks into the low pressure section, and the defrosting operation ends and each indoor unit operates only for heating, or each indoor unit operates for cooling and heating at the same time. At the same time, during a transient period after the heat exchanger on the heat source equipment side switches to operation as an evaporator, the refrigerant at the inlet of the third flow rate control device does not become a supercooled liquid and may be in a flash state. , the noise of the refrigerant flowing through the third flow rate control device can be suppressed to a low level, and the noise of the repeater can be reduced.

In addition, each indoor unit can be operated only for cooling, or each indoor unit can be operated simultaneously for cooling and heating, and the heat exchanger on the heat source side functions as a condenser, or each indoor unit can be operated only for heating, or During a transient period after each indoor unit is simultaneously cooled and heated and the heat exchanger on the heat source side is switched to operation as an evaporator, the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means The third flow rate control device is configured to prevent the opening degree of the third flow rate control device from exceeding a certain opening degree until the subcooling at the inlet of the third flow rate control device calculated from the above reaches a preset value. Since the transient flow rate control device control means for controlling the flow rate control device is provided, each indoor unit is operated only for cooling, or each indoor unit is operated for cooling and heating at the same time, and the heat exchanger on the heat source side functions as a condenser. During a transition period after the operation switches from operation to operation in which each indoor unit performs only heating operation, or operation in which each indoor unit is operated at the same time as cooling and heating, and the heat exchanger on the heat source side functions as an evaporator, the four-way valve is turned off. In turn, the high pressure and intermediate pressure drop temporarily, and the liquid refrigerant in the intermediate pressure part evaporates and leaks into the low pressure part, and the refrigerant at the inlet of the third flow rate control device does not become a supercooled liquid. Even in the flush state, the noise of the refrigerant flowing through the third flow rate control device can be suppressed to a low level, and the noise of the repeater can be reduced.

[0027] In addition, each indoor unit can be operated only for heating, or each indoor unit can be operated simultaneously for cooling and heating, and the heat exchanger on the heat source side functions as an evaporator, or each indoor unit can be operated only for cooling, or During a transient period after each indoor unit is simultaneously cooled and heated and the heat exchanger on the heat source side is switched to operation as a condenser, the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means are The third flow rate control device is configured to prevent the opening degree of the third flow rate control device from exceeding a certain opening degree until the subcooling at the inlet of the third flow rate control device calculated from the above reaches a preset value. Since the transient flow rate control device control means for controlling the flow rate control device is provided, each indoor unit is operated only for heating, or each indoor unit is operated for cooling and heating at the same time, and the heat exchanger on the heat source equipment side functions as an evaporator. During a transition period after the operation is switched from operation to operation in which each indoor unit performs cooling only, or operation in which each indoor unit is operated at the same time as cooling and heating and the heat source equipment side heat exchanger functions as a condenser, the second The superheated gas refrigerant filling the connecting pipe is supplied to the repeater after switching, so the four-way valve switches and the high and intermediate pressures temporarily drop, and the liquid refrigerant in the intermediate pressure part evaporates, reducing the low pressure. Even if the refrigerant at the inlet of the third flow rate control device does not become a supercooled liquid and is in a flash state, it is possible to suppress the noise of the refrigerant flowing through the third flow rate control device. As a result, the noise of the repeater can be reduced.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram centered on a refrigerant system of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram for explaining the operating state of only cooling or heating of the air conditioner according to the first embodiment of the present invention.

FIG. 3 is a refrigerant circuit diagram for explaining the heating-based operating state of the air conditioner according to the first embodiment of the present invention.

FIG. 4 is a refrigerant circuit diagram for explaining the cooling-based operating state of the air conditioner according to the first embodiment of the present invention.

FIG. 5 is a refrigerant circuit diagram for explaining the operating state of the defrosting operation of the air conditioner according to the first embodiment of the present invention.

FIG. 6 is a block diagram for explaining the control contents of the third flow rate control device during a transient period of the air conditioner according to the first embodiment of the present invention.

FIG. 7 is a flowchart for explaining the control contents of the third flow rate control device during a transient period of the air conditioner according to the first embodiment of the present invention.

FIG. 8 is an overall configuration diagram centered on the refrigerant system of an air conditioner according to a second embodiment of the present invention.

[Explanation of symbols]

1 Compressor 2 Four-way switching valve 3 Heat source machine side heat exchanger 4 Accumulator 5 Indoor side heat exchanger 6, 6b, 6c, 6d First connection pipe 7, 7b, 7
c, 7d Second connection pipe 8 Valve device 9 First flow rate control device 10 First branch section 11 Second branch section 12 Gas-liquid separation device 13 Second flow rate control device 14 Bypass piping 15 Third flow rate Control devices 16a, 16b, 16c, 16d, 19 Heat exchange section 17 Fourth flow rate control device 32, 33, 34, 35 Third, fourth, fifth, sixth check valve 40 Heat source machine side switching valve 41 Transient flow rate control device control means 25 First pressure detection means 26 Second pressure detection means 27 Temperature detection means A Heat source equipment B, C, D Indoor unit E Relay

Claims (4)

[Claims] [Claim 1] A compressor, a four-way valve, a heat exchanger on the heat source machine side,
One heat source device consisting of an accumulator and a plurality of indoor units consisting of an indoor heat exchanger and a first flow rate control device are connected via first and second connection pipes, and the plurality of indoor units are connected via first and second connection pipes. a first branching section equipped with a valve device for switchably connecting one of the indoor heat exchangers of the indoor units to the first connection pipe or the second connection pipe; a second branch section connected to the other side of the inner heat exchanger via the first flow rate control device and connected to the second connection pipe via the second flow rate control device; A bypass pipe is provided which is connected to the first connecting pipe via the second flow rate control device, one end of which is connected to the second branch portion, and the other end of which is connected to the first connection pipe via the third flow rate control device. A second pressure detection means and a temperature detection means are provided between the second flow control device and the third flow control device, the first branch part, the second branch part, and the second flow control device. , wherein a repeater incorporating the third flow rate control device, the second pressure detection means, and the temperature detection means is interposed between the heat source device and the plurality of indoor units; After the compressor is started, until the subcool at the inlet of the third flow rate control device, which is calculated from the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means, reaches a preset value. The simultaneous heating and cooling system is characterized by comprising a transient flow rate control device control means for controlling the third flow rate control device so that the opening degree of the third flow rate control device does not exceed a certain opening degree. Operable air conditioner. [Claim 2] After the defrosting operation is completed and each indoor unit is operated only for heating, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source equipment side is switched to operation as an evaporator. , until the subcool at the inlet of the third flow rate control device calculated from the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means reaches a preset value. 2. The flow rate control device according to claim 1, further comprising transient flow rate control device control means for controlling said third flow rate control device so that the opening degree of said third flow rate control device does not exceed a certain opening degree. Air conditioner. Claim 3: Each indoor unit is operated only for cooling, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source equipment side functions as a condenser, and each indoor unit is operated only for heating, or After each indoor unit is simultaneously cooled and heated and the heat exchanger on the heat source side is switched to operation as an evaporator, the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means are calculated. Until the subcool at the inlet of the third flow rate control device reaches a preset value,
Claim 1, further comprising transient flow rate control device control means for controlling said third flow rate control device so that the opening degree of said third flow rate control device does not exceed a certain opening degree. Air conditioner as described in section. Claim 4: Each indoor unit is operated only for heating, or each indoor unit is operated simultaneously for cooling and heating, and the heat exchanger on the heat source side functions as an evaporator, and each indoor unit is operated only for cooling, or After each indoor unit is simultaneously cooled and heated and the heat exchanger on the heat source side is switched to operation as a condenser, the temperature is calculated from the pressure detected by the second pressure detection means and the temperature detected by the temperature detection means. Until the subcool at the inlet of the third flow rate control device reaches a preset value,
Claim 1, further comprising transient flow rate control device control means for controlling said third flow rate control device so that the opening degree of said third flow rate control device does not exceed a certain opening degree. Air conditioner as described in section.