JP2601052B2 - 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.
Further, the present invention relates to an air conditioner capable of simultaneously performing cooling in one indoor unit and heating in the other indoor unit.

[0002]

2. Description of the Related Art Conventionally, a heat pump type air conditioner in which a plurality of indoor units are connected to one heat source unit by two pipes of a gas pipe and a liquid pipe to perform a cooling and heating operation is generally used. The machines are all configured to heat or all cool.

[0003]

Since the conventional multi-chamber heat pump type air conditioner is configured as described above, all the indoor units are operated only for cooling or heating. However, there is a problem that cooling is performed in a place where heating is required. In particular, when installed in a large-scale building, there is a particular problem because the load of air conditioning is significantly different between an interior unit and a perimeter unit, or a general office room and a computer room or other OAized room. As an approximation technique, there is JP-A-1-134172.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. A plurality of indoor units are connected to one heat source unit, and air conditioning is selectively performed for each indoor unit. In addition, if one indoor unit is installed in a large-scale building so that cooling can be performed simultaneously and the other indoor unit can be heated at the same time, the OA of the interior and perimeter, or the general office and computer room, etc. It is an object of the present invention to obtain a multi-chamber heat pump type air conditioner capable of coping with a significantly different air conditioning load in each of the rooms.
It is another object of the present invention to reduce the refrigerant flow noise during transition.

[0005]

An air conditioner according to the present invention comprises a plurality of indoor units each having a single heat source unit including a compressor, a switching valve, and a heat source unit side heat exchanger, and an indoor side heat exchanger. Connected to the heat source via the first and second connection pipes, and provided between the first and second connection pipes to switch the direction of the flowing refrigerant so that the heat source is always operated during operation. A flow path switching valve device that lowers the pressure of the first connection pipe and the pressure of the second connection pipe interposed between the unit and the indoor unit, and one of the indoor heat exchangers of the plurality of indoor units Through the first connection pipe or the gas-liquid separator.
A first branch portion connecting the second to switchable example the connecting pipe Te, the other indoor heat exchanger of the plurality of indoor units first
A second branch portion connected to the second connection pipe via the flow control device of the above , and provided in the second connection pipe,
The first connection through the second flow control device that will be connected between the gas-liquid separator and the second branch portion, the one end and the other end connected to the second branch portion bypass flow control device A bypass circuit connected to the pipe, a second pressure detecting means for detecting a refrigerant pressure between the second flow control device and the bypass flow control device, the second flow control device and the bypass flow control device; Temperature detecting means for detecting a refrigerant temperature between the flow rate control device and the bypass flow rate calculated from the detected pressure of the second pressure detecting means and the detected temperature of the temperature detecting means after the compressor is started. Until the degree of supercooling at the inlet of the control device reaches a preset value, the bypass flow control device is controlled so that the opening of the bypass flow control device does not exceed a certain opening. Set flow control device control means Those were.

[0006] Further, 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 operation is switched to an operation in which the heat exchanger on the heat source unit side becomes an evaporator. the second until the detected pressure and the inlet of the subcooling degree of the bypass flow control device, which is calculated from the detected temperature of the temperature detecting means of the pressure detecting means reaches a preset value, the bypass provided that controls the bypass flow control device flow amount control device controlling means not to exceed a certain degree with the opening of the use flow control device.

[0007] In addition, from the operation in which each indoor unit only operates for cooling or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat source unit side heat exchanger serves as a condenser, the operation in which each indoor unit operates only for heating, or After each indoor unit is operated simultaneously with cooling and heating, and the heat source unit side heat exchanger is switched to an operation to be an evaporator,
Until the degree of supercooling at the inlet of the bypass flow 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, the bypass providing the bypass flow control device that controls the flow amount control device controlling means not to exceed a certain degree that the opening degree of the flow control device.

[0008] In addition, from the operation in which each indoor unit is operated only for heating or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat source unit side heat exchanger is an evaporator , the operation for each indoor unit is only for cooling, or After each indoor unit is operated simultaneously with cooling and heating, and after the heat source unit side heat exchanger is switched to an operation to be a condenser ,
Until the degree of supercooling at the inlet of the bypass flow 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, the bypass providing the bypass flow control device that controls the flow amount control device controlling means not to exceed a certain degree that the opening degree of the flow control device.

[0009]

In the present invention, at the time of transition after the start of the compressor, the refrigerant at the inlet of the bypass flow control device does not become supercooled liquid and does not the state, until the subcooling degree reaches a preset value so as not to exceed a certain degree with the opening degree of the bypass flow control device, the bypass <br/> flow controller The noise of the refrigerant flowing through the air is kept low.

Further, during the defrosting operation, the high pressure is low, and the liquid refrigerant in the intermediate pressure portion between the second flow control device and the bypass flow control device passes through the low pressure portion. When the operation is completed and each indoor unit is operated only for heating, or each indoor unit is simultaneously operated for cooling and heating, and during the transition after the heat source unit side heat exchanger is switched to the operation to be an evaporator,
The refrigerant at the inlet of the bypass flow control device is not in the supercooled liquid and is in a flush state, and the opening degree of the bypass flow control device is maintained until the supercooling degree reaches a preset value. So that it does not exceed a certain opening,
The refrigerant flow noise flowing through the bypass flow control device is suppressed to be small.

[0011] Further, from the operation in which each indoor unit is operated only for cooling or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat exchanger on the heat source unit side is a condenser, the operation in which each indoor unit is only for heating, or the transient state after each indoor unit is the heat source apparatus side heat exchanger while being simultaneous heating and cooling operation is switched to operation as an evaporator, the high pressure and intermediate pressure temporarily decreases switched is switched valve, above The refrigerant at the inlet of the bypass flow control device is not in the supercooled liquid but is in a flush state,
Until the degree of supercooling reaches the preset value,
The flow rate of the refrigerant flowing through the bypass flow control device is suppressed to a low level so that the opening of the bypass flow control device does not exceed a certain opening.

[0012] Further, from the operation in which each indoor unit is operated only for heating, or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat exchanger on the heat source unit side is an evaporator, the operation for each indoor unit is only for cooling, or At the time of transition after each indoor unit is simultaneously operated for cooling and heating and after the operation of the heat source unit side heat exchanger is switched to a condenser, the second connection pipe before switching is filled.
Since Ruga scan refrigerant is supplied to the second branch portion after switching, the refrigerant inlet of the bypass flow control device is a flash state not become the supercooled liquid, the bypass
The flow rate of the refrigerant flowing through the bypass flow rate control device is suppressed to a small level so that the opening degree of the flow rate control device does not exceed a certain opening degree.

[0013]

[Embodiment 1] Hereinafter, embodiments of the present invention will be described. FIG. 1 is an overall configuration diagram mainly showing a refrigerant system of an air conditioner according to an embodiment of the present invention. FIGS. 2 to 4 show the operation states during the cooling / heating operation in the embodiment of FIG.
FIG. 2 shows an operation state diagram of only cooling or heating, and FIGS. 3 and 4 show an operation of simultaneous cooling and heating operation. FIG. 3 mainly shows heating (when the heating operation capacity is larger than the cooling operation capacity).
FIG. 4 is an operation state diagram showing a cooling main body (when the cooling operation capacity is larger than the heating operation capacity), and FIG. 5 is an operation state diagram of the defrosting operation. FIG. 8 is an overall configuration diagram mainly showing a refrigerant system of an air conditioner according to another embodiment of the present invention. In this embodiment, the indoor unit 3 is connected to one heat source unit.
The case where two or more indoor units are connected 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 is a first branch, a second flow controller, a second branch, a gas-liquid separator, a heat exchanger, and a third and fourth flow controllers as bypass flow controllers, as described later. It is a repeater with a built-in device. 1 compressor, 2 changeover valve for switching a refrigerant flow direction of the heat source machines, 3 heat source apparatus side heat exchanger, 4 is an accumulator, the device is connected, the heat source unit A is configured by these. 5 three indoor units B, C, D it
Indoor heat exchanger provided in the Le, 6 thick first connection pipe connecting the repeater E a switching valve 2 of the heat source unit A, 6b, 6
c and 6d respectively connect the indoor side heat exchangers 5 of the indoor units B, C and D and the relay E, and a first connection pipe on the indoor unit side corresponding to the first connection pipe 6, and 7 is a heat source unit. A second connection pipe, 7b, 7c, 7d, which is thinner than the first connection pipe connecting the heat source unit side heat exchanger 3 of A and the repeater E, is an indoor heat exchanger of the indoor units B, C, D, respectively. Connection pipe on the indoor unit side connecting the relay 5 and the relay E via the first flow control device 9
And corresponds to the second connection pipe 7. 8 is switchably connected to the first connection pipe 6b, 6c, 6d on the indoor unit side and the first connection pipe 6 or the second connection pipe 7 side, and the first connection pipe on the indoor unit side. 6b, 6c, 6d
A three-way switching valve 9 capable of closing the flow to any one of the first connection pipe 6 and the second connection pipe 7 is connected in close proximity to the indoor heat exchanger 5, and the indoor heat exchange during cooling is performed. The first flow control device is controlled by the superheat amount on the outlet side of the unit 5 and the subcool amount during heating, and is connected to the second connection pipes 7b, 7c, 7d on the indoor unit side. Reference numeral 10 denotes a first branch portion including a first connection pipe 6b, 6c, 6d on the indoor unit side and a three-way switching valve 8 switchably connected to the first connection pipe 6 or the second connection pipe 7. 11 and the second connection pipe 7b of the indoor unit side, 7c, 7 d and a second branch portion made of the second connection pipe 7, 12 gas-liquid separator provided in the middle of the second connecting pipe 7 The gas layer is connected to the first port 8a of the three-way switching valve 8, and the liquid layer is connected to the second branch 11
It is connected to the. 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, and reference numeral 14 denotes a second branch portion 1.
1 and the first connection pipe 6 by a bypass circuit (this
Bypass pipe) in Examples 15 bypass flow
In this embodiment, a third flow control device (here, an electric expansion valve) provided in the middle of the bypass pipe 14 corresponds to a control device . 16a is the bypass pipe 1
The provided 4 of course it provided downstream of the third flow controller 15, of the indoor unit side in the second branch portion 11 and the second connection pipe 7b, 7c, between the meeting part of 7d A second heat exchange section for performing heat exchange, 16b, 16c, 1
6d On provided in the middle of the bypass pipe 14, respectively
Serial third provided downstream of the flow control device 15, of the indoor unit side in the second branch portion 11 and the second connection pipe 7b, 7
A third heat exchanging unit 19 for exchanging heat with c and 7d is provided downstream of the third flow control device 15 in the bypass pipe 14 and downstream of the second heat exchanging unit 16a. The first heat exchange section 17 for exchanging heat between the pipe connecting the liquid separation device 12 and the second flow control device 13 is also provided.
Further, it is an openable / closable bypass flow control device connected between the second branch portion 11 and the first connection pipe 6 ,
A fourth flow control device (here, an electric expansion valve) 32 in this embodiment is provided with a third check provided between the heat source unit side heat exchanger 3 and the second connection pipe 7. A valve from the heat source unit side heat exchanger 3 to the second connection pipe 7
Only the refrigerant flow is allowed. 33 is a cutoff of the heat source unit A.
Conversion valve 2 and the fourth provided between the first connection pipe 6
A check valve, allowing only the refrigerant flow into the switching valve 2 from the first connection pipe 6. 34 is the heat source device A
A fifth check valve which is provided between the changeover valve 2 and the second connection pipe 7, allowing only the refrigerant flow into the second connection pipe 7 from the switching valve 2. 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 is provided from the first connection pipe 6 to the heat source unit side heat exchanger. Only the refrigerant flow to 3 is allowed. The third, fourth, fifth, and sixth check valves 32, 33, 34, 35
Constitutes the flow path switching valve device 40. 49 is the flow path switching
During the above channel switching of the valve device 40 and the second connection pipe 7
The heat-source-unit-side bypass passage 48 that connects between the valve-changing device 40 and the first connection pipe 6.
A sixth solenoid on-off valve, which is provided in the middle of the pipe 9 and controls the opening and closing of the heat-source-unit-side bypass 49, a 25 The first pressure detecting means 26 is connected to the second flow control device 13.
Second pressure detecting means 27 provided between the first and third and fourth flow control devices 15 and 17 is a temperature detecting means provided at the inlet of the third flow control device 15.

An embodiment of the present invention configured as described above will be described. First, the case of only the cooling operation will be described with reference to FIG. That is, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the switching valve 2 and exchanges heat with air in the heat source unit-side heat exchanger 3 to be condensed and liquefied as indicated by solid arrows in FIG. After that, the third check valve 32, the second connection pipe 7, the gas-liquid separation device 12, the second flow control device 13, and the second branch portion 11, the second unit on the indoor unit side in this order. It flows into each indoor unit B, C, D through the connection piping 7b, 7c, 7d. Then, the refrigerant flowing into each of the indoor units B, C, D is
The pressure is reduced to a low pressure by the first flow control device 9 controlled by the amount of superheat at the outlet of each indoor heat exchanger 5, and the indoor heat exchanger 5 exchanges heat with indoor air to evaporate and gasify. Cool. The gaseous refrigerant is supplied to the first connection pipes 6b, 6c, 6d on the indoor unit side,
Three-way switching valve 8, first branch portion 10, first connection pipe 6,
The fourth check valve 33, switching valve 2 of the heat source machine, a circulation cycle is drawn into the compressor 1 through the accumulator 4 constitutes,
Perform cooling operation. At this time, the first port 8 of the three-way switching valve 8
a is closed, and the second port 8b and the third port 8c are open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure, the first connection pipe 6 necessarily flows to the third check valve 32 and the fourth check valve 33. In this cycle, a part of the refrigerant that has passed through the second flow control device 13
4, the pressure is reduced to a low pressure by the third flow control device 15, and the second connection pipes 7b, 7c, 7d on the indoor unit side of the second branch portion 11 in the third heat exchange sections 16b, 16c, 16d. Between the second heat exchange section 16a and the associated section of the second connection pipes 7b, 7c, 7d on the indoor unit side of the second branch section 11, and further, the first heat exchange section. 19 the evaporated refrigerant exchanges heat with the refrigerant flowing into the second flow controller 13, the first connection pipe 6, the heat source apparatus of the switching valve 2 enters the fourth check valve 33, the accumulator 4 and is sucked into the compressor 1. 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 heat exchange at a, 16b, 16c, and 16d and 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, high-temperature high-pressure refrigerant gas discharged from the compressor 1 as indicated by the dotted arrow in the figure passes through the switching valve 2, the fifth check valve 34, the second connection pipe 7, the gas-liquid separator 12 Through the first branch portion 10, the three-way switching valve 8, and the first connection pipes 6b, 6c, 6d on the indoor unit side, flow into the indoor units B, C, D, and exchange heat with the indoor air. To condense and liquefy and heat the room. Then, 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 pipe 7b on the indoor unit side. , 7c, 7d
And flows into the second branch portion 11 to merge therewith .
Through the flow control device 17. Here, the pressure is reduced to a low-pressure gas-liquid two-phase state by one of the first flow control device 9 and the third and fourth flow control devices 15 and 17. Then, 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 through the first connection pipe 6, where it exchanges heat with air and evaporates. refrigerant becomes gas state, switching valve 2 of the heat source machines, the accumulator 4 constitutes a circulation cycle is drawn into the compressor 1 through the performs heating operation. At this time, in the three-way switching valve 8, the second port 8b is closed, and the first port 8a and the third port 8c are open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure at this time, the fifth check valve 34 and the sixth
To the check valve 35.

Referring to FIG. 3, a description will be given of a case in which heating and cooling are simultaneously performed in the simultaneous cooling and heating operation. That is, 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 as shown by a dotted arrow in FIG. 12 and then through the first branch 10, the three-way switching valve 8, and the first connection pipes 6b and 6c on the indoor unit side in the order of each of the indoor units B to be heated.
C, and heat exchanges with indoor air in the indoor heat exchanger 5 to condense and liquefy and heat the room. Then, the condensed and liquefied refrigerant is controlled by the subcooling amounts at the outlets of the indoor side heat exchangers B and C, passes through the first flow control device 9 which is almost fully opened, and is slightly depressurized and flows into the second branch portion 11. I do. A part of the refrigerant is supplied to the second connection pipe 7d on the indoor unit side.
After entering the indoor unit D to be cooled through the air conditioner and entering the first flow control device 9 controlled by the superheat amount at the outlet of the indoor heat exchanger D, the pressure is reduced, and then the indoor heat exchanger 5
After entering, heat exchange to evaporate to a gas state to cool the room and flow into the first connection pipe 6 via the three-way switching valve 8. 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 refrigerant 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 after being cooled by the indoor unit D to be cooled. And evaporate to a gaseous state. Then, the refrigerant switching valve 2 of the heat source machines, the accumulator 4 constitutes a circulation cycle is drawn into the compressor 1 through the, perform the heating dominant 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 to switch to the thick first connection pipe 6. At this time, the second port 8b of the three-way switching valve 8 connected to the indoor units B and C is closed, 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 the third port 8c are open. At this time, the refrigerant is supplied to the first connection pipe 6
Flows through the fifth check valve 34 and the sixth check valve 35 inevitably because the pressure is low and the second connection pipe 7 is 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, 7c, 7d on the indoor unit side of the second branch section 11, and enters the third flow control device. The pressure is reduced to a low pressure at 15 and the third heat exchange units 16b, 16c, 16d
And the second connection pipe 7 on each indoor unit side of the second branch portion 11
b, 7c, 7d, the second heat exchange section 16a
Connection pipes 7b, 7 on each indoor unit side of the branch portion 11
c, the refrigerant evaporated by thermal exchange with the meeting part of 7d, the first connection pipe 6, the sixth check valve of the heat source unit enters the 35 switching valve 2, the compressor 1 through the accumulator 4 Inhaled. On the other hand, the second and third heat exchange units 16a, 16b, 1
The refrigerant in the second branch portion 11, which has been cooled by the heat exchange at 6c and 16d and has been sufficiently subcooled, flows into the indoor unit D to be cooled.

Referring to FIG. 4, a description will be given of a case where cooling and heating are mainly performed at the same time. That is, the refrigerant gas discharged from the compressor 1 flows into the heat source device side heat exchanger 3 and exchanges heat with the air there, as shown by the solid line arrow in FIG. . After that, the two-phase high-temperature 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. Then, here, the gaseous refrigerant and the liquid refrigerant are separated, and the separated gaseous refrigerant is heated in the order of the first branch portion 10, the three-way switching valve 8, and the first connection pipe 6d on the indoor unit side. 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 slightly reduced through the first flow control device 9 which is controlled by the subcooling amount at the outlet of the indoor heat exchanger 5 and is almost fully open, and flows into the second branch portion 11. On the other hand, the remaining liquid refrigerant flows into the second branch portion 11 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. Then, the refrigerant merges with the refrigerant that has passed through the indoor unit D to be heated. And the second branch 1
1. Follow the order of the second connection pipes 7b and 7c on the indoor unit side,
It flows into each of the indoor units B and C. 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 and is gasified to cool the room. Further, the refrigerant in this gaseous state passes through the first connection pipes 6b and 6c, the three-way switching valve 8, and the first branch portion 10 on the indoor unit side, and passes through the first connection pipe 6 and the fourth connection pipe 4.
The check valve 33, the switching valve 2 of the heat source machine, via the accumulator 4 constitutes a circulation cycle is sucked into the compressor 1 performs the cooling main operation. 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 opened.
Is closed, and the first port 8a and the third port 8c are open. At this time, since the first connection pipe 6 has a low pressure and the second connection pipe 7 has a high pressure 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 flows from the junction of the second connection pipes 7b, 7c, 7d on the indoor unit side of the second branch section 11 to the bypass pipe 14
Then, the pressure is reduced to a low pressure by the third flow control device 15, and the second branch 1 is formed by the third heat exchange units 16b, 16c, and 16d.
The second connection pipes 7b, 7c, 7d on the side of each indoor unit of the second branch unit 11 in the second heat exchange unit 16a between the second connection pipes 7b, 7c, 7d on the side of each indoor unit of FIG. , 7d, and further in the first heat exchange section 19, the second flow control device 1
The refrigerant evaporated by thermal exchange with the refrigerant flowing into the 3, the first connection pipe 6, switching valve 2 of the heat source machine enters the fourth check valve 33, sucked into the compressor 1 through the accumulator 4 Is done. 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, the case of the defrosting operation will be described with reference to FIG. Since the sixth solenoid on-off valve 48, the second flow control device 13 , and the third flow control device 15 are open, the second connection is performed immediately after the start of the defrosting operation, as indicated by the broken line arrow in FIG. Most of the high-temperature and high-pressure gas refrigerant that has filled the pipe 7 flows to the low-pressure side through the heat source device-side bypass passage 49,
The fourth check valve 33, flows into the accumulator 4 fart switching valve 2, a slight remaining gas-liquid separator 12, the second flow controller 13, to a low pressure through a third flow controller 15 The pressure is reduced, and flows into the accumulator 4 via the first connection pipe 6, the fourth check valve 33, and the switching valve 2. Also, high-temperature high-pressure refrigerant gas after the gas refrigerant in the second connection pipe 7 has passed through the low pressure side is discharged from the compressor 1 as shown by the solid line arrows through the switching valve 2, the heat source unit side heat exchanger 3 After being condensed and liquefied by heat exchange with frost, most of the refrigerant is reduced to a low pressure through the third non-return valve 32 through the heat source device side bypass passage 49, and a small amount of the remaining refrigerant is supplied to the second connection pipe. 7. Gas-liquid separation device 1
As in the order of 2, the pressure 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. After the refrigerant and the refrigerant which has flowed through the heat source apparatus side bypass passage 49 through the repeater E is merged at the inlet portion of the fourth check valve 33, compressed through fourth check valve 33, switching valve 2, an accumulator 4 Flows into the machine 1. Since the circulation cycle is formed in this manner, the amount of heat of the refrigerant that has filled the second connection pipe 7 before the start of the defrosting operation, the amount of heat of the second connection pipe 7, and the amount of heat of the repeater E are quickly collected. The frost that has formed on the heat source device side heat exchanger 3 can be reliably melted. In addition, immediately after the start of the defrosting operation, most of the high-temperature and high-pressure gas refrigerant that has filled the second connection pipe 7 flows to the low-pressure side through the heat-source-unit-side bypass passage 49, and the second flow control device 13 , Third flow
Since a small amount of refrigerant passes through the amount control device 15, the high-temperature and high-pressure gas refrigerant is supplied to the second flow control device 13 and the third flow control device 1
The sound passing through 5 is small. In addition, the heat exchanger 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 device side bypass passage 49, and thus reduced to a low pressure by the second flow control device 13 or the third flow control device 15. And the refrigerant flowing into the second and third flow control devices 13 and 15 is sufficiently cooled by the first and second heat exchangers 19 and 16a to become a liquid refrigerant. The noise of the refrigerant passing through the third flow control devices 13 and 15 is small.

Next, control contents of the third flow control device 15 during a transition after the compressor 1 is started will be described. Compressor 1
At the time of transition after startup, the refrigerant at the inlet of the third flow control device 15 is in a flush state without being supercooled liquid because the high pressure has not sufficiently risen. When the degree exceeds a certain opening degree, the flow noise of the refrigerant passing through the third flow control device 15 increases. Therefore, the third flow control device 15 is controlled as described below to suppress the flow noise. FIG. 6 is a block diagram showing the control contents of the third flow control device 15 during a transition. 41 is a transient flow control device control means. FIG.
5 is a flowchart showing the operation of the third flow control device 15 during a transition. In step 50, the second pressure detecting means 2
The subcool SC at the inlet of the third flow control device 15 is calculated from the detected pressure 6 and the temperature detected by the temperature detecting means 27. Next, it is determined whether or not 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 S of the third flow control device 15 is larger than a certain opening S0, and if S ≦ S0, the process returns to step 50. . On the other hand, if S> S0, then at step 53 S =
The process returns to step 50 as S0. As described above, when the refrigerant is in a flush state at the entrance of the third flow control device 15, the opening is restricted to reduce the refrigerant flow noise, and the sub-cool is sufficiently taken at the entrance of the third flow control device 15 and the refrigerant is removed. Since the restriction on the opening degree is released after the flowing sound becomes smaller, noise can be reduced.

Embodiment 2 FIG. Next, a transition after the defrosting operation is completed and each indoor unit is operated only for heating, or each indoor unit is simultaneously operated for cooling and heating and is switched to an operation in which the heat source unit side heat exchanger 3 becomes an evaporator. The control contents of the third flow control device 15 at this time will be described. During defrosting operation, high pressure is low,
Since the liquid refrigerant in the intermediate pressure portion between the second flow control device 13 and the third flow control device 15 passes through the low pressure portion,
During the transition after the defrosting operation is completed and each indoor unit is operated only for heating, or each indoor unit is simultaneously operated for cooling and heating and after the heat source unit side heat exchanger 3 is switched to the operation of becoming an evaporator,
The refrigerant at the inlet of the third flow control device 15 is not in a supercooled liquid state but is in a flush state, and when the opening of the third flow control device 15 exceeds a certain opening, the third flow control device The flow noise of the refrigerant passing through 15 increases. Therefore, in order to reduce the flow noise, the third flow control device 1
When the refrigerant is in a flush state at the entrance of the fifth flow controller, the opening is restricted, and the restriction of the opening is released after the subcool is sufficiently taken at the entrance of the third flow control device 15 and the refrigerant flow noise is reduced. The specific control contents of the third flow control device 15 are the same as those at the time of transition after the start of the compressor 1, and thus the description thereof is omitted here.

Embodiment 3 FIG. Next, from the operation in which each indoor unit operates only for cooling or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat source unit side heat exchanger 3 becomes a condenser, the operation in which each indoor unit operates only for heating, or the operation in each indoor unit The control contents of the third flow control device 15 during a transition after the heat-source-unit-side heat exchanger 3 is switched to the operation to be the evaporator when the units are simultaneously operated for cooling and heating will be described. From the operation in which each indoor unit is operated only for cooling or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat source unit side heat exchanger 3 is a condenser, the operation for each indoor unit is only for heating, or each indoor unit is cooled or heated. the transient state after the heat source apparatus side heat exchanger 3 is switched to operation as an evaporator together with the simultaneous operation, a high pressure and the intermediate pressure is cut behalf changeover valve 2 is temporarily reduced, the liquid in the intermediate pressure portion Since the refrigerant evaporates and passes through the low-pressure portion, the refrigerant at the inlet of the third flow control device 15 is not in the supercooled liquid but is in a flush state, and the opening degree of the third flow control device 15 is reduced. When the opening exceeds a certain degree, the flow noise of the refrigerant passing through the third flow control device 15 increases. Therefore, in order to suppress the flow noise, when the refrigerant is in a flush state at the entrance of the third flow control device 15, the opening degree is limited, and the sub flow is sufficiently taken at the entrance of the third flow control device 15 and the refrigerant flow is reduced. Release the restriction on the opening after the sound becomes low. The specific control contents of the third flow control device 15 are the same as those at the time of transition after the start of the compressor 1, and thus the description thereof is omitted here.

Embodiment 4 FIG. Next, from the operation in which each indoor unit is operated only for heating or the operation in which each indoor unit is simultaneously operated for cooling and heating and the heat source unit side heat exchanger 3 is an evaporator, the operation for each indoor unit is only for cooling, or each indoor unit is operated only for cooling. The control contents of the third flow control device 15 during a transition after the operation of the heat exchanger and the heat exchanger at the same time and the heat source unit side heat exchanger 3 is switched to the operation of the condenser will be described. From the operation in which each indoor unit is operated only for heating or the operation in which each indoor unit is simultaneously operated for cooling and heating and the heat source unit side heat exchanger is an evaporator, the operation for each indoor unit is only for cooling,
Alternatively, at the time of the transition after the indoor units are simultaneously operated for cooling and heating and the operation is switched to the operation in which the heat source unit side heat exchanger becomes the condenser 3, the superheated gas refrigerant filling the second connection pipe 7 before switching is used. Since it is supplied to the repeater E after switching,
The refrigerant at the inlet of the third flow control device 15 is not in a supercooled liquid state but is in a flush state, and when the opening of the third flow control device 15 exceeds a certain opening, the third flow control device The flow noise of the refrigerant passing through 15 increases. Therefore, in order to reduce the flow noise, the third flow control device 1
When the refrigerant is in a flush state at the entrance of the fifth flow controller, the opening is restricted, and the restriction of the opening is released after the subcool is sufficiently taken at the entrance of the third flow control device 15 and the refrigerant flow noise is reduced. The specific control contents of the third flow control device 15 are the same as those at the time of transition after the start of the compressor 1, and thus the description thereof is omitted here.

Embodiment 5 FIG. In the above embodiment, the three-way switching valve 8 is provided to provide the first connection pipes 6b, 6c, 6 on the indoor unit side.
and d is connected to the first connection pipe 6 or the second connection pipe 7 so as to be switchable. As shown in FIG. 8, two solenoid valves 30 and 31 are provided to open and close the valve. The same operation and effect can be obtained even if the connection is made switchable.

[0024]

As described above, the air conditioner of the present invention has a single heat source unit including a compressor, a switching valve, and a heat source side heat exchanger, and a plurality of indoor units each having an indoor side heat exchanger. the indoor unit, the first, that is connected via a second connection pipe, the first, is provided between the second connection pipe, by switching the direction of refrigerant flow, always during operation, the A flow path switching valve device for lowering the pressure of the first connection pipe and a high pressure of the second connection pipe interposed between the heat source unit and the indoor unit, and an indoor heat exchanger of the plurality of indoor units. One through the first connection pipe or the gas-liquid separation device
A first branch portion connecting the second to switchable example the connecting pipe Te, the other indoor heat exchanger of the plurality of indoor units first
A second branch portion connected to the second connection pipe via the flow control device of the above , and provided in the second connection pipe,
The first connection through the second flow control device that will be connected between the gas-liquid separator and the second branch portion, the one end and the other end connected to the second branch portion bypass flow control device A bypass circuit connected to the pipe, a second pressure detecting means for detecting a refrigerant pressure between the second flow control device and the bypass flow control device, the second flow control device and the bypass flow control device; Temperature detecting means for detecting a refrigerant temperature between the flow rate control device and the bypass flow rate control calculated from the detected pressure of the second pressure detecting means and the detected temperature of the temperature detecting means after the start of the compressor. Flow control device control for controlling the bypass flow control device so that the opening of the bypass flow control device does not exceed a predetermined opening until the degree of subcooling at the inlet of the device reaches a preset value. Because we have the means After the compressor is started, the high pressure does not rise sufficiently, so that the refrigerant at the inlet of the bypass flow control device does not become a supercooled liquid but is in a flush state even though the refrigerant flows through the bypass flow control device. Sound can be suppressed to a low level and noise can be reduced.

Further, after the defrosting operation is completed, each indoor unit is operated only for heating, or after each indoor unit is operated simultaneously for cooling and heating and the operation is switched to the operation in which the heat exchanger on the heat source unit side becomes an evaporator. the until the detected pressure and the inlet of the subcooling degree of the temperature detecting means detecting the bypass flow control device which is calculated from the temperature of the second pressure detecting means reaches a predetermined value, the flow control the bypass since with the flow that controls the bypass flow control device quantity control unit control means so as not to exceed a certain degree with the opening of the device, high pressure low during the defrosting operation, the second flow rate controller and the intermediate pressure portion of the liquid refrigerant between the bypass <br/> flow control equipment is gone missing the low pressure portion, the operation of each indoor unit defrosting operation is finished heating only, or the indoor The heat source side side heat After exchanger is switched to operation as an evaporator, also the inlet of the refrigerant of the bypass flow control device is a flash state does not become supercooled liquid, the bypass <br/> flow controller noise reduction can be achieved to suppress the refrigerant flow noise flowing you to <br/>.

The operation of each indoor unit only for cooling, or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat source unit side heat exchanger is a condenser, the operation for each indoor unit only for heating, or After each indoor unit is operated simultaneously with cooling and heating, and the heat source unit side heat exchanger is switched to an operation to be an evaporator ,
Until the detected pressure value to the inlet of the subcooling degree is set in advance of the bypass flow control device, which is calculated from the detected temperature of the temperature detecting means of the second pressure detecting means, the bypass flow control device The bypass flow control device is controlled so that the opening of the bypass does not exceed a certain opening.
Since with the that flow amount control device controlling means, switch the switching valve
Thus, from the operation in which each indoor unit operates only for cooling, or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat source unit side heat exchanger serves as a condenser, the operation in which each indoor unit operates only for heating, or After the indoor unit is operated simultaneously with cooling and heating, and the heat source unit side heat exchanger is switched to an operation to be an evaporator ,
Reduced pressure and the intermediate pressure temporarily, an intermediate pressure portion of the liquid refrigerant evaporates, also the inlet of the refrigerant of the bypass flow control device is a flash state without becoming the supercooled liquid, the Ba
Bypass flow control device Ki out possible to reduce the refrigerant flow noise through the noise reduction can be achieved.

[0027] Further, from the operation in which each indoor unit is operated only for heating or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat exchanger on the heat source unit side is an evaporator, the operation for each indoor unit is only for cooling, or After each indoor unit is operated simultaneously with cooling and heating, and after the heat source unit side heat exchanger is switched to an operation to be a condenser ,
Until the detected pressure value to the inlet of the subcooling degree is set in advance of the bypass flow control device, which is calculated from the detected temperature of the temperature detecting means of the second pressure detecting means, the bypass flow control device The bypass flow control device is controlled so that the opening of the bypass does not exceed a certain opening.
Since with the that flow amount control device controlling means, the heat source apparatus side heat exchanger from the operation as an evaporator together with the operation of the indoor unit is heated only, or the indoor units are cooling and heating simultaneous operation, the indoor units after There was switched to the operation in which the heat source apparatus side heat exchanger becomes the condenser with the operation of the cooling only, or the indoor units are cooling and heating simultaneous operation, Ruga scan meet the second connecting pipe prior to switching the refrigerant is supplied to the second branch portion after switching, also the inlet of the refrigerant of the bypass flow control device is a flash state without becoming the supercooled liquid, the Bi
Ki out possible to reduce the refrigerant flow noise flowing path for flow controller noise reduction can be achieved.

[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 is a refrigerant circuit diagram for describing an operation state of a defrosting operation of the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 6 is a block diagram for explaining control contents of a third flow control device during a transition of the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 7 is a flow chart for explaining control contents of a third flow control device in a transient state of the air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 8 is an overall structural view of an air conditioner according to Embodiment 2 of the present invention, centering on a refrigerant system.

[Explanation of symbols]

1 compressor, 2 switching valve, 3 heat exchanger side heat exchanger, 4
Accumulator, 5 indoor heat exchanger, 6, 6b, 6c,
6d first connection pipe, 7, 7b, 7c, 7d second connection pipe, 8 valve device, 9 first flow control device, 10
1st branch section, 11 2nd branch section, 12 gas-liquid separation device, 13 2nd flow control device, 14 bypass piping, 15 bypass flow control device, 16a, 16b,
16c, 16d, 19 heat exchange section, 17 bypass flow control device, 32, 33, 34, 35 third, fourth, fifth, sixth check valves, 40 flow path switching valve device , 41 flow amount control device controlling means, 25 first pressure detecting means, 26
Second pressure detecting means, 27 temperature detecting means, A heat source device,
B, C, D indoor unit, E repeater.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tokuaki Hayashida 6-66, Tehira, Wakayama-shi Mitsubishi Electric Corporation Wakayama Works (72) Inventor Shigeo Takada 6-5-66, Tehira, Wakayama-shi Mitsubishi Electric Inside Wakayama Works, Ltd. (72) Inventor Junichi Kameyama 6-66, Teira, Wakayama City Mitsubishi Electric Wakayama Works, Ltd.

Claims (4)

(57) [Claims] 1. A first and a second connection pipe for connecting one heat source unit comprising a compressor, a switching valve and a heat source unit side heat exchanger and a plurality of indoor units each having an indoor side heat exchanger. Connected between the first and second connection pipes, and by switching the direction of the flowing refrigerant, the first operation interposed between the heat source unit and the indoor unit is always performed during operation. A flow path switching valve device for setting the pressure of the connection pipe to low pressure and the pressure of the second connection pipe to high pressure; and connecting the one of the indoor heat exchangers of the plurality of indoor units to the first connection pipe or gas-liquid separation. apparatus
A first branch portion connecting the second connecting pipe to the switching e capable through, the plurality of indoor units of the indoor side heat exchanger while the first flow control device the second via A second branch connected to the connection pipe; and a second branch provided in the second connection pipe and connected between the gas-liquid separator and the second branch.
A second flow control device that Re, one end is connected to the second branch portion, and a bypass circuit connected to the first connection pipe and the other end through the bypass flow control device, the second
The flow control device and the second pressure detecting means for detecting the refrigerant pressure between the bypass flow control device, said second flow control device and the upper Symbol temperature detection means for detecting the refrigerant temperature between the bypass flow control device And after the compressor is started, supercooling of the refrigerant on the inflow side of the bypass flow control device calculated from the detected pressure detected by the second pressure detecting means and the detected temperature detected by the temperature detecting means. Air flow control means for controlling the opening degree of the bypass flow control apparatus so that the opening degree does not exceed a predetermined opening degree until the degree reaches a preset value. Harmony equipment. 2. A compressor, a switching valve, one heat source equipment consisting of heat source apparatus side heat exchanger, and a plurality of indoor units having a indoor heat exchanger, respectively, first, second connection pipe Connected between the first and second connection pipes, and by switching the direction of the flowing refrigerant, the first operation interposed between the heat source unit and the indoor unit is always performed during operation. A flow path switching valve device for setting the pressure of the connection pipe to low pressure and the pressure of the second connection pipe to high pressure; and connecting the one of the indoor heat exchangers of the plurality of indoor units to the first connection pipe or gas-liquid separation. apparatus
A first branch portion that is switchably connected to a second connection pipe via a second connection pipe, and the other of the indoor heat exchangers of the plurality of indoor units is connected to the second connection pipe via a first flow control device. A second branch connected to a pipe, and a second branch provided in the second connection pipe and connected between the gas-liquid separator and the second branch.
A second flow control device that Re, one end is connected to the second branch portion, and a bypass circuit connected to the first connection pipe and the other end through the bypass flow control device, the second
Pressure detecting means for detecting the refrigerant pressure between the flow control device and the bypass flow control device, and temperature detecting means for detecting the refrigerant temperature between the second flow control device and the bypass flow control device. After the defrosting operation is completed and each indoor unit is operated only for heating, or each indoor unit is simultaneously operated for cooling and heating and the operation is switched to the operation in which the heat source unit side heat exchanger becomes an evaporator, Until the degree of supercooling at the inlet of the bypass flow control device calculated from the pressure detected by the pressure detection means and the temperature detected by the temperature detection device reaches a preset value, the bypass flow control device An air conditioner comprising a flow control device control means for controlling the opening so as not to exceed a certain opening. 3. A first and a second connection pipe for connecting one heat source unit comprising a compressor, a switching valve and a heat source unit side heat exchanger and a plurality of indoor units each having an indoor side heat exchanger. Connected between the first and second connection pipes, and by switching the direction of the flowing refrigerant, the first operation interposed between the heat source unit and the indoor unit is always performed during operation. A flow path switching valve device for setting the pressure of the connection pipe to low pressure and the pressure of the second connection pipe to high pressure; and connecting the one of the indoor heat exchangers of the plurality of indoor units to the first connection pipe or gas-liquid separation. apparatus
A first branch portion that is switchably connected to a second connection pipe via a second connection pipe, and the other of the indoor heat exchangers of the plurality of indoor units is connected to the second connection pipe via a first flow control device. A second branch connected to a pipe, and a second branch provided in the second connection pipe and connected between the gas-liquid separator and the second branch.
A second flow control device that Re, one end is connected to the second branch portion, and a bypass circuit connected to the first connection pipe and the other end through the bypass flow control device, the second
The flow control device and the second pressure detecting means for detecting the refrigerant pressure between bypass flow control device, the second flow controller and the temperature detection means for detecting the refrigerant temperature between the bypass flow control device From the operation in which each indoor unit is operated only for cooling or the operation in which each indoor unit is simultaneously operated for cooling and heating and the heat source unit side heat exchanger is a condenser, the operation for each indoor unit is only for heating, or each indoor unit is Are operated simultaneously with cooling and heating, and the operation is switched to an operation in which the heat source device side heat exchanger becomes an evaporator. Then, the bypass calculated from the detection pressure of the second pressure detection means and the detection temperature of the temperature detection means Until the degree of supercooling at the inlet of the flow control device reaches a preset value, the bypass flow control device is controlled so that the opening of the bypass flow control device does not exceed a certain opening. Controlled flow rate control An air conditioning apparatus characterized by comprising a device control means. 4. A first and a second connection pipe for connecting one heat source unit comprising a compressor, a switching valve and a heat source unit side heat exchanger and a plurality of indoor units each having an indoor side heat exchanger. Connected between the first and second connection pipes, and by switching the direction of the flowing refrigerant, the first operation interposed between the heat source unit and the indoor unit is always performed during operation. A flow path switching valve device for setting the pressure of the connection pipe to low pressure and the pressure of the second connection pipe to high pressure; and connecting the one of the indoor heat exchangers of the plurality of indoor units to the first connection pipe or gas-liquid separation. apparatus
A first branch portion that is switchably connected to a second connection pipe via a second connection pipe, and the other of the indoor heat exchangers of the plurality of indoor units is connected to the second connection pipe via a first flow control device. A second branch connected to a pipe, and a second branch provided in the second connection pipe and connected between the gas-liquid separator and the second branch.
A second flow control device that Re, one end is connected to the second branch portion, and a bypass circuit connected to the first connection pipe and the other end through the bypass flow control device, the second
Pressure detecting means for detecting the refrigerant pressure between the flow control device and the bypass flow control device, and temperature detecting means for detecting the refrigerant temperature between the second flow control device and the bypass flow control device. From the operation in which each indoor unit is operated only for heating, or the operation in which each indoor unit is simultaneously operated for cooling and heating and the operation in which the heat source unit side heat exchanger is an evaporator, the operation for each indoor unit is only for cooling, or each indoor unit is operated for cooling only After the cooling / heating operation is performed simultaneously and the operation is switched to the operation in which the heat source device side heat exchanger becomes a condenser, the bypass for the bypass calculated from the detected pressure of the second pressure detecting means and the detected temperature of the temperature detecting means is used. Until the degree of supercooling at the inlet of the flow control device reaches a preset value, the bypass flow control device is controlled so that the opening of the bypass flow control device does not exceed a certain opening. Flow rate system An air conditioning apparatus characterized by comprising a device control means.