JP3092421B2 - Multi-room 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 air conditioner having a plurality of refrigerant circuits.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, there is a multi-room air conditioner having an outdoor unit 41 and four indoor units 42 connected to the outdoor unit 41. The outdoor unit 41 has a compressor (not shown) and an outdoor heat exchanger (not shown), connects the outdoor unit 41 and the indoor unit 42,
It constitutes a refrigerant circuit.

[0003]

By the way, in the above-mentioned multi-room air conditioner, when frost adheres to the outdoor heat exchanger during the heating operation, the heating operation is stopped and defrosting is performed.
There is a problem that the temperature of the outlet of the indoor unit 42 decreases and the room temperature decreases.

[0004] The outdoor unit 4 of the multi-room air conditioner described above.
The outdoor heat exchanger (1) has a disadvantage that it takes a long time to defrost because of its large capacity. For this reason, at the time of defrost, since the heating stop time becomes long, the room temperature tends to decrease and it is easy to be uncomfortable.

Accordingly, an object of the present invention is to provide a multi-room air conditioner capable of continuing a heating operation even during defrost and suppressing a decrease in room temperature.

[0006]

According to a first aspect of the present invention, there is provided a multi-room air conditioner in which a compressor, a four-way valve, an outdoor heat exchanger, and at least one indoor unit are sequentially connected. In the multi-room air conditioner having a plurality of refrigerant circuits, the outdoor heat exchanger of one of the refrigerant circuits is connected to the indoor unit, and the outdoor heat exchanger of the other refrigerant circuit is connected to the indoor unit. A state in which the outdoor heat exchanger of the one refrigerant circuit is connected to the indoor unit of the other refrigerant circuit, and the outdoor heat exchanger of the other refrigerant circuit is connected to the indoor unit of the one refrigerant circuit. A state in which the four-way valve of the one refrigerant circuit is connected to the outdoor heat exchanger, and the four-way valve of the other refrigerant circuit is connected to the outdoor heat exchanger; The four-way valve of one refrigerant circuit and the outdoor heat exchanger of the other refrigerant circuit It continued, and is characterized in that a second switching valve that switches to a state that connects the outdoor heat exchanger four-way valve and said one refrigerant circuit of the other refrigerant circuit.

[0007] The multi-room air conditioner according to claim 2 is
2. The multi-room air conditioner according to claim 1, wherein frost formation detecting means for detecting frost formation on the outdoor heat exchanger of one of the refrigerant circuits, and wherein the frost formation detection means comprises the outdoor heat exchanger of the one refrigerant circuit. 3. When the frost formation is detected, the first switching valve is connected to the outdoor heat exchanger of the one refrigerant circuit and the indoor unit of the other refrigerant circuit based on a signal from the frost detection means. Then, the state is switched to a state in which the outdoor heat exchanger of the other refrigerant circuit and the indoor unit of the one refrigerant circuit are connected, and the second switching valve is connected to the four-way valve of the one refrigerant circuit and the other side. Switching valve control means for connecting a four-way valve of the other refrigerant circuit to the outdoor heat exchanger of the one refrigerant circuit by connecting the outdoor heat exchanger of the refrigerant circuit of After the means has switched the first and second switching valves, the other cooling valve is switched. A compressor starting means for starting the compressor of the medium circuit;
And a four-way valve control means for switching the four-way valve of the other refrigerant circuit to the cooling side after switching the switching valve.

[0008] The multi-room air conditioner according to claim 3 is characterized in that:
3. The multi-room air conditioner according to claim 2, wherein defrost end determining means for determining whether defrost of the outdoor heat exchanger of said one refrigerant circuit has ended, and said outdoor heat exchange from said defrost end determining means. Compressor stop means for stopping the compressor of the other refrigerant circuit in response to a signal indicating that defrosting of the compressor has been completed, and a four-way valve return for returning the four-way valve of the other refrigerant circuit to the heating side. Means.

Further, the multi-room air conditioner of claim 4 is:
In a multi-room air conditioner having a plurality of refrigerant circuits in which a compressor, a four-way valve, an outdoor heat exchanger, and at least one indoor unit are sequentially connected, the outdoor heat exchanger of one of the refrigerant circuits and the indoor unit Connected, the state of connecting the outdoor heat exchanger of the other refrigerant circuit and the indoor unit, and connecting the outdoor heat exchanger of the one refrigerant circuit and the indoor unit of the other refrigerant circuit,
A first switching valve for switching between an outdoor heat exchanger of the other refrigerant circuit and an indoor unit of the one refrigerant circuit, and a line connecting the indoor unit and the compressor of the one refrigerant circuit; And a bypass line that connects a line connecting the indoor unit and the compressor of the other refrigerant circuit to each other;
An on-off valve arranged on the bypass line to open and close the bypass line.

The multi-room air conditioner according to claim 5 is
The multi-room air conditioner according to claim 4, wherein the frost detection means for detecting frost formation on the outdoor heat exchanger of one of the refrigerant circuits, and the frost formation detection means detects the frost of the one refrigerant circuit on the heating operation side. When detecting frost formation on the outdoor heat exchanger, the first switching valve is switched between the outdoor heat exchanger of the one refrigerant circuit and the room of the other refrigerant circuit based on a signal from the frost detection means. Valve control means for connecting the outdoor heat exchanger of the other refrigerant circuit to the indoor unit of the one refrigerant circuit, and opening the on-off valve arranged in the bypass line. It is characterized by having.

[0011]

According to the multi-room air conditioner of the first aspect,
When the one refrigerant circuit performs the heating operation and the other refrigerant circuit is stopped, when the frost adheres to the outdoor heat exchanger of the one refrigerant circuit on the heating operation side, the first switching valve is switched. The outdoor heat exchanger of the one refrigerant circuit is connected to the indoor unit of the other refrigerant circuit, and the outdoor heat exchanger of the other refrigerant circuit is connected to the indoor unit of the one refrigerant circuit. Then, the second switching valve is switched to connect the four-way valve of the one refrigerant circuit and the outdoor heat exchanger of the other refrigerant circuit, and to connect the four-way valve of the other refrigerant circuit and the one refrigerant circuit. Connect to outdoor heat exchanger. That is, the outdoor heat exchangers of the respective refrigerant circuits are exchanged by switching the first and second switching valves. Then, one refrigerant circuit on the heating operation side performs heat exchange with an outdoor heat exchanger that is not frosted,
Continue heating operation.

As described above, when only one of the refrigerant circuits is in the heating operation, even if the outdoor heat exchanger of one of the refrigerant circuits is frosted, the first and second switching valves are used. By switching between the outdoor heat exchanger of one refrigerant circuit and the outdoor heat exchanger of the other refrigerant circuit, the heating operation can be continued.

[0013] According to the multi-room air conditioner of the second aspect, in the multi-room air conditioner of the first aspect, the one refrigerant circuit is heated and the other refrigerant circuit is stopped. When the frost is formed on the outdoor heat exchanger of one of the refrigerant circuits and the frost detection means detects the frost on the outdoor heat exchanger, the switching valve control means performs frost detection. Means for connecting the first switching valve to the outdoor heat exchanger of one refrigerant circuit and the indoor unit of the other refrigerant circuit, and connecting the outdoor heat exchanger of the other refrigerant circuit to one refrigerant. The circuit is switched to a state of connecting to the indoor unit, and the second switching valve is connected to the four-way valve of one refrigerant circuit and the outdoor heat exchanger of the other refrigerant circuit, and is connected to the four-way valve of the other refrigerant circuit. The state is switched to a state in which the valve is connected to the outdoor heat exchanger of one of the refrigerant circuits. Then, the one refrigerant circuit performs heat exchange with the outdoor heat exchanger that is not frosted, and continues the heating operation.
Further, the compressor of the other refrigerant circuit was started by the compressor starting means, and the four-way valve of the other refrigerant circuit was switched to the cooling side by the four-way valve control means, and the high-temperature and high-pressure refrigerant gas was frosted. Defrost the outdoor heat exchanger by sending it to the outdoor heat exchanger.

Therefore, when the outdoor heat exchanger of one refrigerant circuit is frosted, the heating operation can be continued by switching between the outdoor heat exchanger of one refrigerant circuit and the outdoor heat exchanger of the other refrigerant circuit. Also, start the compressor of the other refrigerant circuit,
By switching the four-way valve to the cooling side, the frosted outdoor heat exchanger can be defrosted. Therefore, even if it takes a long time to defrost the outdoor heat exchanger of one refrigerant circuit, the heating operation is continuously performed using the outdoor heat exchanger of the other refrigerant circuit. Comfort can be improved.

According to the multi-room air conditioner of the third aspect, in the multi-room air conditioner of the second aspect, it is determined whether or not the defrost of the outdoor heat exchanger has been completed. When the signal indicating that defrosting of the outdoor heat exchanger has been completed is received from the defrost end determining means, the compressor stopping means stops the compressor of the other refrigerant circuit. Then, the four-way valve of the other refrigerant circuit is returned to the heating side by the four-way valve return means.

Therefore, when the defrost of the outdoor heat exchanger is completed by the other refrigerant circuit, the compressor of the other refrigerant circuit is stopped, and the four-way valve of the refrigerant circuit is returned to the normal operation state. You can go back.

Further, according to the multi-room air conditioner of the fourth aspect, when the one refrigerant circuit is operated for heating and the other refrigerant circuit is stopped, the outdoor heat exchange of the one refrigerant circuit is performed. When frost adheres to the heat exchanger, the first switching valve is switched to connect the one outdoor heat exchanger and the other indoor unit, and the outdoor heat exchanger of the other refrigerant circuit and the indoor space of the one refrigerant circuit are connected. A line connecting the indoor unit and the compressor of the one refrigerant circuit and a line connecting the indoor unit and the compressor of the other refrigerant circuit. They communicate with each other via a bypass line. Then, the four-way valve of the one refrigerant circuit is switched to the cooling side,
By sending the high-temperature and high-pressure refrigerant gas to the frosted outdoor heat exchanger, the outdoor heat exchanger is defrosted. Thus, the room in which the indoor unit of the other refrigerant circuit is installed is used as a heat source to defrost the outdoor heat exchanger.

Therefore, when only one of the refrigerant circuits is in the heating operation, defrosting is performed by using the room on the stop side as a heat source, so that a decrease in the room temperature on the heating operation side can be suppressed.

According to the multi-room air conditioner of the fifth aspect, in the multi-room air conditioner of the fourth aspect, the one refrigerant circuit is operated for heating and the other refrigerant circuit is stopped. When frost adheres to the outdoor heat exchanger of one of the refrigerant circuits and the frost detection means detects the frost of the outdoor heat exchanger, the valve control means Based on the signal, the valve control means switches the first switching valve and opens the on-off valve. By switching the first switching valve, the outdoor heat exchanger of the one refrigerant circuit and the indoor unit of the other refrigerant circuit are connected, and the outdoor heat exchanger of the other refrigerant circuit and the indoor of the one refrigerant circuit are connected. A line connecting the indoor unit and the compressor of the one refrigerant circuit, and a line connecting the indoor unit and the compressor of the other refrigerant circuit by opening the on-off valve. Are communicated with each other via a bypass line. Then, by switching the four-way valve of the one refrigerant circuit to the cooling side, and sending the high-temperature and high-pressure refrigerant gas to the frosted outdoor heat exchanger,
Defrost the outdoor heat exchanger.

Therefore, when the outdoor heat exchanger of the one refrigerant circuit is frosted, the indoor unit of one refrigerant circuit and the indoor unit of the other refrigerant circuit can be switched, and the room on the stop side is used as a heat source. Then, defrosting can be performed to suppress a decrease in room temperature on the heating operation side.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a multi-chamber air conditioner of the present invention will be described in detail with reference to embodiments.

(First Embodiment) FIG. 1 is a circuit diagram of a multi-room air conditioner according to a first embodiment of the present invention, wherein 1 is a compressor, and 2 is a compressor connected to the compressor 1. An outdoor heat exchanger connected to the four-way valve 2 via a line 31 is connected to a branch line 3 at the other end of the outdoor heat exchanger 3.
Expansion valves 6 and 7 are connected at one end via 3a, 33b and 33c, respectively, and indoor units 6 and 7 are connected to the other ends of the expansion valves 4 and 5, respectively. The other end of each of the indoor units 6, 7 and the compressor 1 are connected via branch lines 35a, 35b, 35c.
The closing valve 9 is disposed on the branch line 33a, and the accumulator 8 and the closing valve 10 are disposed on the branch line 35a in order from the compressor 1 side. The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the expansion valves 4, 5, the indoor units 6, 7, the accumulators 8, and the shutoff valves 9, 10 constitute an A-system refrigerant circuit. The outdoor heat exchanger 3
Is provided with a frost detection sensor 3a as frost detection means for detecting frost.

Reference numeral 11 denotes a compressor, and 12 denotes the compressor 1
1 is a four-way valve, 13 is an outdoor heat exchanger connected to the cut-off four-way valve 12 via a line 32, and 14 and 15 are the outdoor heat exchanger 13 and branch lines 34a, 34b, 34c.
The expansion valves 16 and 17 are connected to the other ends of the expansion valves 14 and 15, respectively. The other end of each of the indoor units 14 and 15 and the compressor 11 are connected via branch lines 36a, 36b and 36c. The branch line 34a is provided with the closing valve 19, while the branch line 36a is provided with the accumulator 18 and the closing valve 20 in order from the compressor 11 side. The compressor 11
, Four-way valve 12, outdoor heat exchanger 13, expansion valves 14, 15, indoor units 16, 17, accumulator 18, closing valves 19,2.
0 constitutes a B-system refrigerant circuit. The outdoor heat exchanger 13 is provided with a frost detection sensor 13a as frost detection means for detecting frost.

A line 33a connecting the outdoor heat exchanger 3 of the A-system refrigerant circuit to the shut-off valve 9 and a line 34a connecting the outdoor heat exchanger 13 of the B-system refrigerant circuit 13 to the shut-off valve 19 are provided. It is arranged a switching valve V ₁ to. On the other hand, a line 31 connecting the four-way valve 2 of the A-system refrigerant circuit and the outdoor heat exchanger 3 and a line 32 connecting the four-way valve 12 of the B-system refrigerant circuit and the outdoor heat exchanger 13 are provided. It is disposed switching valve V _2. The switching valve V ₁ connects the outdoor heat exchanger 3 of the A system to the closing valve 9, and the outdoor heat exchanger 13 of the B system
And the state in which the system is connected to the closing valve 19, the system A outdoor heat exchanger 3 is connected to the system B closing valve 19, and the system B outdoor heat exchanger 13 is connected to the system A closing valve 9. Switch to state. On the other hand, the switching valve V ₂ is a four-way valve ₂ of the A system.
And the outdoor heat exchanger 3 and the B-system four-way valve 12 and the outdoor heat exchanger 13 are connected, and the A-system four-way valve 2 is connected.
And the outdoor heat exchanger 13 of the B system is connected, and the state is switched to the state of connecting the four-way valve 12 of the B system and the outdoor heat exchanger 3 of the A system. That is, by switching the switching valves V ₁ and V ₂ , the A-system outdoor heat exchanger 3 is connected to the B-system refrigerant circuit, and the B-system outdoor heat exchanger 13 is connected to the A-system refrigerant circuit. Thus, the outdoor heat exchangers 3 and 13 can be exchanged in the refrigerant circuits of the A and B systems.

Further, between the closing valve 10 and the four-way valve 2 of the A-system branch line 35a and the B-system branch line 36a
Is connected to the vicinity of the accumulator 18 by a bypass line 37, and the on-off valve SV ₃ is connected to the bypass line 37.
Is arranged. In addition, the branch line 36a of the B system
Between the shutoff valve 20 and the four-way valve 12 and the vicinity of the accumulator 8 in the branch line 35a of the A system.
8 and the on-off valve S
It is disposed V _4.

The multi-room air conditioner includes a control unit 40 for controlling the cooling and heating operation. The control unit 40 includes a switching valve control unit, a four-way valve control unit,
The compressor includes a compressor starting unit, a defrost end determining unit, a compressor stopping unit, and a four-way valve returning unit. The switching valve control means, for example, performs the heating operation of the refrigerant circuit of system A and, when the system B is stopped, detects that frost formation is detected from the frost detection sensor 3a of the outdoor heat exchanger 3 of system A. In response to the signal, the first and second switching valves V ₁ and V ₂ are switched. Thereafter, the four-way valve control means switches the B-side four-way valve 12 on the stop side to the cooling side. Then, the compressor starting means starts the compressor 11 on the stop side. The defrost end determining means determines whether or not the defrost of the outdoor heat exchanger 3 of the A system has been completed, and the compressor stopping means has determined that the defrost of the outdoor heat exchanger 3 of the A system has been completed. At this time, the compressor 11 of the B system is stopped. Further, the four-way valve returning means returns the B-system four-way valve 12 to the heating side.

The multi-room air conditioner of the above configuration performs a heating operation in accordance with the flowchart shown in FIG. In the flowchart of FIG. 2, the refrigerant circuit of the A system is operated for heating and the refrigerant circuit of the B system is stopped. However, even if the refrigerant circuit of the B system is operated for heating and the refrigerant circuit of the A system is stopped. Good.

First, in step S1, the heating operation of the A-system refrigerant circuit is performed, and the process proceeds to step S2 to check whether the outdoor heat exchanger 3 of the A-system is frosted. That is,
A signal indicating whether or not frost is detected from the frost detection sensor 3a of the outdoor heat exchanger 3 is confirmed. If the outdoor heat exchanger 3 of the A system is frosted in step S2, the process proceeds to step S3. If the outdoor heat exchanger 3 of the A system is not frosted, the process returns to step S1.

Next, at step S3, the switching valves V ₁ and V ₂ are switched. That is, the outdoor heat exchanger 3 of the A system and the outdoor heat exchanger 13 of the B system are exchanged. Then, in step S4, the B-system compressor 11 is started, and in step S5, the B-system four-way valve 12 is turned on to switch to the cooling side.

Next, in step S6, it is confirmed whether or not the defrost of the outdoor heat exchanger 3 of the A system has been completed. If the defrost of the outdoor heat exchanger 3 has been completed, the process proceeds to step S7.
On the other hand, if the defrost of the outdoor heat exchanger 3 is not completed, the process returns to step S4. Then, step S7
Then, the compressor 11 of the B system is stopped. Next, step S
Proceeding to 8, the four-way valve 12 of the B system is turned off and switched to the heating side. Next, in step S9, it is confirmed whether or not to operate the B-system refrigerant circuit. If the B-system refrigerant circuit is not operated, the process returns to step S1.

On the other hand, when the B-type refrigerant circuit is operated in step S9, the process proceeds to step S10, where the on-off valves SV ₃ , SV
And the V ₄ is opened a predetermined time, A, the refrigerant and lubricating oil in the refrigerant circuit of the B lineage in a uniform state. At this time, flow through the B lineage pressure refrigerant of system A is passed through the on-off valve SV _3, on-off valve S
Hardly flows to V _4. On the other hand, the B-type and heating operation, if you have to stop the system A, flows into the system A high-pressure refrigerant system B through the opening and closing valve SV _4, hardly flows through the on-off valve SV _3.

As described above, when one of the refrigerant circuits A and B is operated for heating and the other is stopped, for example, A
When the refrigerant circuit of the system is operated for heating and the refrigerant circuit of the system B is stopped, the control unit 40 controls the outdoor heat exchanger 3 of the system A.
When frost adheres, the switching valves V ₁ and V ₂ are switched based on a signal from the frost detection sensor 3a, and the A-system refrigerant circuit exchanges heat with the B-system outdoor heat exchanger 13. , Heating operation can be continued. The outdoor heat exchanger 3 of the A system can be defrosted by starting the compressor 11 of the B system and switching the four-way valve 12 of the B system to the cooling side. Then, the control unit 40
When the defrost ends, the compressor 11 of the B system is stopped, the four-way valve 12 of the refrigerant circuit of the B system is returned, and the operation can be returned to the normal operation. Therefore, even if it takes a long time to defrost one of the outdoor heat exchangers 3 and 13 of the refrigerant circuits of the A and B systems, the heating operation can be continued by using the other of the outdoor heat exchangers 3 and 13. In addition, a multi-room air conditioner capable of preventing a decrease in room temperature and improving comfort can be realized.

[0033] (Second Embodiment) FIG. 3 illustrates the operation of the defrost of the multi-chamber air conditioner of a second embodiment of the present invention, configuration identical except for the configuration and switching valve V ₂ in FIG. 1 You are. The control unit 40 that controls the cooling and heating operation includes a valve control unit configured by software. The valve control means switches the _first switching valve V1 in response to a signal indicating that frost formation has been detected from the frost formation detection sensors 3a, 13a of the outdoor heat exchangers 3, 13 of the A and B systems. At the same time, the on-off valve S
One of V ₃ and SV ₄ is opened.

Hereinafter, the heating operation is performed according to the flowchart shown in FIG. In addition, although the refrigerant circuit of the A system is operated for heating and the refrigerant circuit of the B system is stopped, the refrigerant circuit of the B system may be operated for heating and the refrigerant circuit of the A system may be stopped.

First, the heating operation of the A system is performed in step S21, and the process proceeds to step S22 to check whether or not the outdoor heat exchanger 3 of the A system is frosted. Step S2 above
If the outdoor heat exchanger 3 of the A system is frosted in step 2, the process proceeds to step S23. If the outdoor heat exchanger 3 of the A system is not frosted, the process returns to step S21 to perform the heating operation. continue.

Next, in step S23, the four-way valve 2 of the A system is turned on to switch to the cooling side. Next, the switching of the switching valve V ₁ at step S24, opens the on-off valve SV _4. That is, the outdoor heat exchanger 3 of the A system is connected to the indoor units 16 and 17 of the B system, and the outdoor heat exchanger 1 of the B system is connected.
3 and the indoor units 6 and 7 of the A system, and a branch line 35a and a branch line 3
6a. Then, in step S25, it is checked whether or not the defrost of the outdoor heat exchanger 3 of the A system has been completed. If the defrost of the outdoor heat exchanger 3 has been completed, the process proceeds to step S26, while the operation of the outdoor heat exchanger 3 If the defrost has not been completed, the process returns to step S23. And
Switching the switching valve V ₁ at step S26, closing the on-off valve SV _4. That is, the outdoor heat exchanger 3 of the A system is connected to the indoor units 6 and 7, the outdoor heat exchanger 13 of the B system is connected to the indoor units 16 and 17, and the branch line 35a is connected.
And the bypass line 38 communicating with the branch line 36a
Close. Next, in step S27, the four-way valve 2 of the A system
Turn off. Next, in step S28, it is confirmed whether or not to operate the B-system refrigerant circuit. If the B-system refrigerant circuit is not operated, the process returns to step S21.

On the other hand, when the refrigerant circuit of the B system is operated in step S28, the process proceeds to step S29, where the on-off valve SV ₃ ,
The SV ₄ is opened for a certain time to make the refrigerant and the lubricating oil in the refrigerant circuits of the A and B systems uniform. And step S
At 30, normal operation is performed.

As described above, when one of the refrigerant circuits A and B is operated for heating and the other refrigerant circuit is stopped, for example, the refrigerant circuit for system A is operated for heating, and
When the refrigerant circuit of the system is stopped, if frost adheres to the outdoor heat exchanger 3 of the refrigerant circuit of the system A, the controller 40
Switches the first switching valve V ₁ to connect the outdoor heat exchanger 3 of the A system to the indoor units 16 and 17 of the B system, and connects the outdoor heat exchanger 13 of the refrigerant circuit of the B system to the outdoor heat exchanger 13 of the A system. The indoor units 6 and 7 of the refrigerant circuit are connected. Then, the control unit 40
By opening the on-off valve SV _4, the indoor unit 6 in the refrigerant circuit of system A,
The branch line 35a connecting the compressor 7 to the compressor 1 and the branch line 36a connecting the indoor units 16 and 17 of the B-system refrigerant circuit and the compressor 1 are connected to each other. afterwards,
The control unit 40 switches the four-way valve 2 of the A-system refrigerant circuit on the heating operation side to the cooling side, and sends the high-temperature and high-pressure refrigerant gas to the frosted outdoor heat exchanger 3 to thereby control the outdoor heat exchanger 3. 3. Defrost 3. That is, the indoor unit 1 of the B system
Using the room where 6, 17 is installed as a heat source, A
The defrost of the outdoor heat exchanger 3 of the system refrigerant circuit is performed.

Therefore, defrosting is performed by using the room on the stop side as a heat source, and the room on the heating operation side is not used as a heat source, so that a decrease in room temperature on the heating operation side can be suppressed.

In the first and second embodiments, the multi-chamber air conditioner has two refrigerant circuits of A and B systems.
The number of refrigerant circuits is not limited to this, and may be a multi-room air conditioner having three or more refrigerant circuits. Further, each of the refrigerant circuits may have at least one indoor unit.

In the first and second embodiments, the first and second switching valves V ₁ and V ₂ are used. However, the switching valve is not limited to this, and a plurality of switching valves may be combined. .

In the second embodiment, the bypass lines 37 and 38 and the on-off valves SV ₃ and SV ₄ are provided. However, the line connecting the indoor unit and the compressor of one refrigerant circuit and the other refrigerant line An on-off valve may be provided in a bypass line that connects a line connecting the indoor unit and the compressor of the circuit to each other.

[0043]

As is clear from the above, the multi-room air conditioner according to the first aspect of the present invention has a refrigerant circuit in which a compressor, a four-way valve, an outdoor heat exchanger, and at least one indoor unit are sequentially connected. A state in which the outdoor heat exchanger of one of the refrigerant circuits is connected to the indoor unit, and the outdoor heat exchanger of the other refrigerant circuit is connected to the indoor unit; A first switching valve for connecting the heat exchanger to the indoor unit of the other refrigerant circuit and connecting the outdoor heat exchanger of the other refrigerant circuit to the indoor unit of the one refrigerant circuit; A state in which the four-way valve of the circuit is connected to the outdoor heat exchanger and the four-way valve of the other refrigerant circuit is connected to the outdoor heat exchanger, and a state in which the four-way valve of one refrigerant circuit is connected to the outdoor of the other refrigerant circuit. Connect the heat exchanger and connect the four-way valve of the other refrigerant circuit to the outdoor heat exchanger of one refrigerant circuit It is obtained by a second switching valve switched between that state.

Therefore, according to the multi-room air conditioner of the first aspect of the present invention, the one refrigerant circuit is operated for heating,
When the other refrigerant circuit is stopped, when frost adheres to the outdoor heat exchanger of one of the refrigerant circuits on the heating operation side, the first and second switching valves are switched, and the outdoor heat of each refrigerant circuit is switched. By exchanging the exchanger, one of the refrigerant circuits exchanges heat with the other non-frosted outdoor heat exchanger, and the heating operation can be continued. Therefore, since the heating operation is not stopped, the room temperature can be maintained at a desired temperature, and the comfort can be improved.

The multi-chamber air conditioner according to the second aspect of the present invention is the multi-chamber air conditioner according to the first aspect.
The frost detection means detects frost on the outdoor heat exchanger of one of the refrigerant circuits, and when the frost detection means detects frost on the outdoor heat exchanger of the one refrigerant circuit, Based on the signal from the detection means, the switching valve control means connects the outdoor heat exchanger of one refrigerant circuit and the indoor unit of the other refrigerant circuit, and connects the outdoor heat exchanger of the other refrigerant circuit and one refrigerant circuit. The first switching valve is switched to a state of connecting to the indoor unit of the first refrigerant circuit, and the switching valve control means connects the four-way valve of one refrigerant circuit to the outdoor heat exchanger of the other refrigerant circuit, and The second switching valve is switched to a state in which the four-way valve of the circuit is connected to the outdoor heat exchanger of one of the refrigerant circuits, and the switching valve control means switches the first and second switching valves, and then switches the other. The compressor of the refrigerant circuit is started by the compressor starting means, and the switching valve control means is operated by the first , After switching the second switching valve,
The four-way valve of the other refrigerant circuit is switched to the cooling side by the four-way valve control means.

Therefore, according to the multi-room air conditioner of the second aspect of the present invention, when the outdoor heat exchanger of one of the refrigerant circuits is frosted, the outdoor heat exchanger of one of the refrigerant circuits is connected to the other of the refrigerant circuits. By switching the outdoor heat exchanger, the compressor of the other refrigerant circuit is started while the heating operation is continued, the four-way valve is switched to the cooling side, and the frosted outdoor heat exchanger can be defrosted. . Therefore, even if it takes a long time to defrost the outdoor heat exchanger of one refrigerant circuit, the heating operation can be continued by using the outdoor heat exchanger of the other refrigerant circuit, so that the lowering of the room temperature is prevented. Therefore, comfort can be improved.

The multi-room air conditioner according to the third aspect of the present invention is the multi-room air conditioner according to the second aspect,
The defrost end determining means determines whether or not defrosting of the outdoor heat exchanger of the one refrigerant circuit has been completed, and receives a signal indicating that defrosting of the outdoor heat exchanger has been completed from the defrost end determining means. The compressor of the other refrigerant circuit is stopped by the compressor stop means, and the four-way valve of the other refrigerant circuit is returned to the heating side by the four-way valve return means.

Therefore, according to the multi-room air conditioner of the third aspect of the present invention, when the defrost of the outdoor heat exchanger is completed by the other refrigerant circuit, the compressor of the other refrigerant circuit is stopped, By returning the four-way valve of the refrigerant circuit, it is possible to return to the normal operation state.

The multi-room air conditioner according to the present invention has a plurality of refrigerant circuits in which a compressor, a four-way valve, an outdoor heat exchanger, and at least one indoor unit are sequentially connected. A switching valve for connecting the outdoor heat exchanger of one of the refrigerant circuits to the indoor unit and connecting the outdoor heat exchanger of the other refrigerant circuit to the indoor unit; The heat exchanger is connected to the indoor unit of the other refrigerant circuit, and the outdoor heat exchanger of the other refrigerant circuit is switched to a state of connecting the indoor unit of the one refrigerant circuit to the one refrigerant circuit. The line connecting the indoor unit and the compressor of the other refrigerant circuit and the line connecting the indoor unit and the compressor of the other refrigerant circuit are connected to each other via a bypass line, and the bypass is provided by an on-off valve arranged in the bypass line. It opens and closes the line.

Therefore, according to the multi-room air conditioner of the fourth aspect of the present invention, the one refrigerant circuit is operated for heating,
When the other refrigerant circuit is stopped, when frost adheres to the outdoor heat exchanger on the one refrigerant circuit side, the first switching valve is switched, the on-off valve is opened, and the four refrigerant circuits of the one refrigerant circuit are opened. By switching the passage valve to the cooling side and sending the high-temperature and high-pressure refrigerant gas to the frosted outdoor heat exchanger, the outdoor heat exchanger can be defrosted. Therefore, when only one of the refrigerant circuits is performing the heating operation, the defrosting is performed using the room on the stop side as a heat source, so that a decrease in the room temperature on the heating operation side can be suppressed.

According to a fifth aspect of the present invention, there is provided the multi-room air conditioner according to the fourth aspect.
Defrosting of the outdoor heat exchanger of the one refrigerant circuit is detected by the frost detecting means, and when the frost detecting means detects frost of the outdoor heat exchanger of the one refrigerant circuit, the frost detecting means The valve control means connects the outdoor heat exchanger of one refrigerant circuit and the indoor unit of the other refrigerant circuit, and controls the outdoor heat exchanger of the other refrigerant circuit and the one refrigerant circuit. The first switching valve is switched so as to be connected to the indoor unit, and the valve control means opens the on-off valve arranged on the bypass line.

Therefore, according to the multi-room air conditioner of the invention of claim 5, the one refrigerant circuit is operated for heating,
When the other refrigerant circuit is stopped, frost adheres to the outdoor heat exchanger of one refrigerant circuit, and when the frost detection means detects frost formation on the outdoor heat exchanger, the valve control means Is
Based on the signal from the frost detection means, the valve control means,
The first switching valve is switched, the on-off valve is opened, and the indoor unit of the one refrigerant circuit is switched to the indoor unit of the other refrigerant circuit. By switching the four-way valve of the one refrigerant circuit to the cooling side and sending the high-temperature and high-pressure refrigerant gas to the frosted outdoor heat exchanger, the outdoor heat exchanger can be defrosted. Therefore, when the outdoor heat exchanger of the one refrigerant circuit is frosted, the indoor unit of the one refrigerant circuit and the indoor unit of the other refrigerant circuit can be switched, and the defrosted room is used as a heat source. In addition, a decrease in the room temperature on the heating operation side can be suppressed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a multi-room air conditioner according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a processing flow of a control unit of the multi-room air conditioner of the first embodiment.

FIG. 3 is a flowchart showing a processing flow of a control unit of the multi-room air conditioner according to the second embodiment of the present invention.

FIG. 4 is a schematic view of a conventional multi-room air conditioner.

[Explanation of symbols]

1,11 ... Compressor, 2,12 ... Four-way valve, 3,13 ... Outdoor heat exchanger, 3a, 13a ... Defrost detection sensor, 4,5,14,15
... expansion valve, 6,7,16,17 ... indoor unit, 8,18 ... accumulator, 9,10,19,20 ... closing valve, 40 ... control unit, V _1, V ₂ ... switching valve, SV _3, SV ₄ … On-off valve.

Continuation of front page (56) References JP-A-4-324075 (JP, A) JP-A-64-67577 (JP, A) JP-A 62-77764 (JP, U) JP-A 52-130252 (JP, A) , U) Shokai 56-47446 (JP, U) Shohei 2-55041 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 47/02 550 F25B 47/02 570 F24F 11/02 102 F25B 13/00 F25B 13/00 104

Claims (5)

(57) [Claims] 1. A compressor (1, 11), a four-way valve (2, 12), an outdoor heat exchanger (3, 13) and at least one indoor unit (6, 7,
16 and 17), the outdoor heat exchanger (3, 13) of one of the refrigerant circuits (A, B) and the indoor unit are provided. (6, 7, 16, 17), and the outdoor heat exchanger (3, 13) of the other refrigerant circuit (A, B) and the indoor unit (6, 7,
16, 17) and the one refrigerant circuit
(A, B) outdoor heat exchanger (3, 13) and the other refrigerant circuit
(A, B) is connected to the indoor unit (6, 7, 16, 17), and the outdoor heat exchanger (3, 13) of the other refrigerant circuit (A, B) is connected to the one refrigerant circuit (A). , B) of the indoor unit and (6,7,16,17) a first switching valve that switches to a state that connects the (V _1), said one refrigerant circuit (a, B) of the four-way valve (2 , 12) and the outdoor heat exchanger (3, 13), and the other refrigerant circuit (A,
B) The state in which the four-way valve (2, 12) is connected to the outdoor heat exchanger (3, 13), and the one-way valve of the one refrigerant circuit (A, B)
(2, 12) and the outdoor heat exchanger of the other refrigerant circuit (A, B)
(3, 13) and the four-way valve (2, 12) of the other refrigerant circuit (A, B) and the outdoor heat exchanger (3, 13) of the one refrigerant circuit (A, B). And a second switching valve (V ₂ ) for switching between the two states. 2. The outdoor heat exchanger of one of the refrigerant circuits (A, B) according to claim 1, wherein:
Frost detection means (3a, 13a) for detecting frost formation of (3, 13)
When the frost detection means (3a, 13a) detects frost formation on the outdoor heat exchanger (3, 13) of the one refrigerant circuit (A, B), 13a), the first switching valve (V ₁ ) is connected to the one refrigerant circuit
(A, B) outdoor heat exchanger (3, 13) and the other refrigerant circuit
(A, B) is connected to the indoor unit (6, 7, 16, 17), and the outdoor heat exchanger (3, 13) of the other refrigerant circuit (A, B) is connected to the one refrigerant circuit (A). , B) to connect to the indoor unit (6, 7, 16, 17) and the second switching valve
(V ₂ ) is connected to the four-way valve (2, 1) of the one refrigerant circuit (A, B).
2) and the outdoor heat exchanger (3, 1) of the other refrigerant circuit (A, B).
3) and a four-way valve of the other refrigerant circuit (A, B).
(2, 12) and the outdoor heat exchanger of the one refrigerant circuit (A, B)
(3, 13) and the switching valve control means for switching to a state that connects (S3), then the switching valve control means (S3) is switched to the first, second switching valve (V _1, V ₂₎ A compressor starting means (S4) for starting the compressor (1, 11) of the other refrigerant circuit (A, B); and the switching valve control means (S3) comprising the first and second switching valves ( after switching the V _1, V _2), characterized by comprising the other of the refrigerant circuit (a, four-way valve B) and the four-way valve control means for switching to the cooling side (S5) a (2,12) Multi-room air conditioner. 3. The outdoor heat exchanger of the one refrigerant circuit (A, B) according to claim 2, wherein:
Defrost end determining means (S6) for determining whether or not the defrost of (3, 13) has ended, and defrost of the outdoor heat exchanger (3, 13) from the defrost end determining means (S6) has ended. The compressor stop means (S7) for stopping the compressor (1, 11) of the other refrigerant circuit (A, B) in response to a signal indicating the above, and four of the other refrigerant circuit (A, B). Four-way valve returning means (S) for returning the two-way valve (2, 12) to the heating side
8) A multi-room air conditioner comprising: 4. A compressor (1, 11), a four-way valve (2, 12), an outdoor heat exchanger (3, 13) and at least one indoor unit (6, 7,
16 and 17), the outdoor heat exchanger (3, 13) of one of the refrigerant circuits (A, B) and the indoor unit are provided. (6, 7, 16, 17), and the outdoor heat exchanger (3, 13) of the other refrigerant circuit (A, B) and the indoor unit (6, 7,
16, 17) and the one refrigerant circuit
(A, B) outdoor heat exchanger (3, 13) and the other refrigerant circuit
(A, B) is connected to the indoor unit (6, 7, 16, 17), and the outdoor heat exchanger (3, 13) of the other refrigerant circuit (A, B) is connected to the one refrigerant circuit (A). , B) and a first switching valve (V ₁ ) for switching to a state of connecting the indoor unit (6, 7, 16, 17) to the indoor unit (6, 7, 16) of the one refrigerant circuit (A, B). 7,16,17)
(35a, 36a) connecting the compressor and the compressor (1, 11)
And the indoor unit (6, 7, 16,) of the other refrigerant circuit (A, B).
17) and the line (35a, 3) connecting the compressor (1, 11).
6a) and bypass lines (37, 38)
On-off valves (SV ₁ , SV ₂ ) arranged on the bypass lines (37, 38) for opening and closing the bypass lines (37, 38)
A multi-room air conditioner comprising: 5. The multi-chamber air conditioner according to claim 4, wherein the outdoor heat exchanger of one of the refrigerant circuits (A, B).
Frost detection means (3a, 13a) for detecting frost formation of (3, 13)
When the frost detection means (3a, 13a) detects frost formation on the outdoor heat exchanger (3, 13) of the one refrigerant circuit (A, B), 13a), the first switching valve (V ₁ ) is connected to the one refrigerant circuit
(A, B) outdoor heat exchanger (3, 13) and the other refrigerant circuit
(A, B) is connected to the indoor unit (6, 7, 16, 17), and the outdoor heat exchanger (3, 13) of the other refrigerant circuit (A, B) is connected to the one refrigerant circuit (A). , B) to connect to the indoor unit (6, 7, 16, 17),
Arranged above off valve _{(37,38) (SV 1, SV} 2) valve control means (S24) for releasing the multi-room air conditioning apparatus characterized by comprising a.