JPH09178247A - Control device for multi-room air conditioner - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] Even when the total value of the air conditioning loads of a plurality of air conditioning target rooms exceeds the maximum value of the control capacity of the outdoor unit, it is possible to increase the room temperature close to a large capacity outdoor unit. A control device for a room air conditioner is provided. SOLUTION: The set room temperature T _s and the detected room temperature T _s
Based on the difference between _a, while the air conditioning load calculating means (13) calculates the air-conditioning load in each indoor unit, with reference to the air conditioning load calculated, priority determining means (21) is larger indoor air conditioning load When the priority order for ensuring the operation performance is determined with the unit as the higher order, the operation switching means (22) sums the calculated air conditioning loads, and the total value S _AB corresponds to the upper limit of the control capability of the outdoor unit. When the predetermined value S _ref1 is exceeded, the indoor unit having the first priority is operated with its required capacity,
The indoor unit whose priority is the second or lower is configured to be operated with a reduced operating capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit.

[0002]

2. Description of the Related Art In a multi-room air conditioner, the control capacity of an outdoor unit is determined in consideration of the total value of the air conditioning loads of a plurality of air-conditioned rooms. However, when each of the plurality of air conditioning target rooms is in an extremely heavy load state, the total value of the air conditioning loads of the plurality of air conditioning target rooms may exceed the control capability of the outdoor unit. If an outdoor unit having a larger control capacity is installed to cope with such a case, even if it is possible to cope with a very large air conditioning load, that is, 1
Although it is possible to raise (or lower) the room temperature to the same extent as an apparatus in which one indoor unit is connected to one outdoor unit, it is inevitable that the outdoor unit becomes large and the apparatus price rises.

Therefore, conventionally, even when the total value of the air-conditioning loads of a plurality of air-conditioned rooms exceeds the maximum capacity of the outdoor unit, even if the room temperature of one room is desired to be raised early, the outdoor unit is desired. Was operated at maximum capacity, and the capacity was distributed evenly to each indoor unit. For this reason, for example, if it is desired to quickly raise the room temperature of one room, the room temperature rises in the same way as the other rooms, and the room temperature rise time of all the air-conditioning objects becomes longer overall. I got it.

The present invention has been made to solve the above-mentioned problems, and even when the total value of the air conditioning loads of a plurality of air-conditioned rooms exceeds the maximum control capacity of the outdoor unit, the outdoor unit of large capacity is provided. It is an object of the present invention to provide a control device for a multi-room air conditioner that enables the start-up of room temperature close to room temperature.

[0005]

In the control device for a multi-room air conditioner according to the present invention, the air conditioning load calculating means determines the air conditioning load for each indoor unit based on the difference between the set room temperature and the detected room temperature. On the other hand, while referring to each of the calculated air conditioning loads, when the priority order determination unit determines the priority order for ensuring the operation performance of the indoor unit with a large air conditioning load as the upper rank, the operation switching unit calculates the calculated air conditioning load. Sum the loads,
When the total value exceeds the predetermined value corresponding to the upper limit of the control capacity of the outdoor unit, the indoor unit with the first priority is operated with the required capacity, and the operation capacity of the indoor unit with the second priority or lower is determined. It is configured to reduce the number of operations.

As a result, even when the total value of the air conditioning loads of the plurality of air conditioning target rooms exceeds the maximum value of the control capacity of the outdoor unit, it is possible to raise the room temperature close to the outdoor unit of large capacity.

In this way, when the air conditioning load of the indoor unit having the first priority falls below the second predetermined value, which is sufficiently smaller than the predetermined value, the operation switching means has been operated so far. The indoor unit having the first priority is reduced in operating capacity, and the indoor unit having the second highest priority is operated with the required capacity.

Further, when the air conditioning loads of all the indoor units become equal to or less than the second predetermined value, the operation switching means operates all the indoor units with the required capacity.

In this case, as a specific method of reducing the operating capacity of the indoor unit, the indoor fan is stopped and the expansion valve is closed, or the indoor fan is operated at the minimum rotation speed and the expansion valve is closed. Either squeeze is adopted.

Further, it is preferable to use a predetermined value corresponding to the maximum value of the control capability of the outdoor unit as the predetermined value when operating only the vehicle having the first priority.

Furthermore, if it is assumed that the second predetermined value for switching the operation corresponds to a value that is less than half the control capacity of the outdoor unit, it reliably corresponds to two or more indoor units. it can.

Incidentally, in response to the necessity of arbitrarily setting the priority order, it is preferable to provide a priority order external setting means capable of arbitrarily setting the priority order from outside instead of the priority order setting means. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments. FIG. 2 is a block diagram showing a schematic configuration of an embodiment of the present invention together with a refrigeration cycle system. In the figure, reference numeral 1 is a compressor, and when performing heating operation, the four-way valve 2 is oriented in the direction indicated by the solid line in the figure, and the gas refrigerant discharged from the compressor 1 passes through the four-way valve 2 and the indoor heat exchanger 3A,
It is distributed to 3B and flows in. These indoor heat exchangers 3A, 3B
Acts as a condenser to release heat, and is accompanied by indoor fans 4A and 4B that promote heat exchange. The liquid refrigerant flowing out from the indoor heat exchangers 3A and 3B joins through the expansion valves 5A and 5B for adjusting the flow rate and the pressure, and flows into the outdoor heat exchanger 6. The outdoor heat exchanger 6 acts as an evaporator and absorbs heat, and is provided with an outdoor fan 7 for promoting the heat exchange. The gas refrigerant flowing out of the outdoor heat exchanger 6 is drawn into the compressor 1 through the four-way valve 2.
In this case, the illustration of the accumulator is omitted for simplification of the drawing. Also, when performing cooling operation, the four-way valve 2
In the direction indicated by the broken line in the figure, the refrigerant is caused to flow in the opposite direction to the heating operation, the indoor heat exchangers 3A and 3B serve as evaporators, and the outdoor heat exchanger 6 serves as a condenser. Indoor heat exchanger described above
3A and the indoor fan 4A constitute an indoor unit 8A of the room A together with the indoor control unit 10A, and similarly, the indoor heat exchanger 3B and the indoor fan 4B together with the indoor control unit 10B the indoor unit 8B of the B room.
Is composed. On the other hand, the above-described compressor 1, four-way valve 2,
The expansion valves 5A and 5B, the outdoor heat exchanger 6 and the outdoor fan 7 constitute an outdoor unit 9 together with the outdoor controller 20.

The indoor control units 10A and 10B and the outdoor control unit 20 each include a microprocessor, which sends and receives signals to and from each other and performs necessary processing.
According to the processing result, the indoor control unit 10A determines that the indoor fan 4A
The indoor control unit 10B controls the indoor fan 4B, and the outdoor control unit 20 controls the compressor 1, the expansion valves 5A and 5B, and the outdoor unit 9.

FIG. 1 is a detailed functional block diagram of a microprocessor included in each of the indoor control units 10A and 10B and the outdoor control unit 20 in the embodiment shown in FIG. Here, the indoor control unit 10A and the indoor control unit 10B are configured in exactly the same manner, and room temperature setting means for respectively setting the room temperature.
11, the room temperature detecting means 12 for detecting the room temperature, the air-conditioning load calculating means 13 for calculating the air-conditioning load of the air-conditioning target room based on each of these outputs and transmitting it to the outdoor controller 20, and from the outdoor controller 20. The indoor fan control means 14 for controlling the indoor fans 4A and 4B based on the command is provided. On the other hand, the outdoor control unit 20 compares the air conditioning loads transmitted from the indoor control units 10A and 10B for each indoor unit, and determines the priority order for operating the indoor unit having the larger air conditioning load as a higher rank. When the order determining means 21 and the calculated air-conditioning load are summed up and the total value exceeds a predetermined value corresponding to the upper limit of the control capacity of the outdoor unit, the indoor unit having the first priority has the required capacity. The operation switching means 22 which operates and reduces the operation capacity of the indoor unit whose priority is second or lower, and the expansion valve 5A according to the command of this operation switching means 22.
A-chamber expansion valve control means 23 for closing and throttling, and B-chamber expansion valve control means 24 for shutting and throttling expansion valve 5B
Similarly, a compressor control means 25 for controlling the capacity of the compressor 1 according to a command from the operation switching means 22 and an outdoor fan control means 26 for operating the outdoor heat exchanger 6 are provided.

The operation of the present embodiment configured as described above will be described in detail below. First, the indoor control unit 10A
Configuring the air conditioning load calculating means 13, in accordance with the difference between the room temperature detected value T _a detected by temperature setting value T _s and room temperature detecting means 12 which is set by the temperature setting means 11, the A chamber as the case In consideration of the volume, the air conditioning load S _A during heating operation is calculated and transmitted to the outdoor control unit 20. Similarly,
Air conditioning load calculating means 13 constituting the indoor control unit 10B is in accordance with the difference between the room temperature detected value T _a detected by temperature setting value T _s and room temperature detecting means 12 which is set by the temperature setting means 11, the heating operation The air conditioning load S _B at the time is calculated and transmitted to the outdoor control unit 20.

Priority determining means constituting the outdoor control unit 20
21 compares the air conditioning loads S _A and S _B transmitted from the indoor control units 10A and 10B, respectively, and designates one indoor unit with a large air conditioning load as the first operation priority order for ensuring its performance. Then, the other indoor unit with the smaller air-conditioning load is designated as the second priority of the operation. The operation switching means 22 is
The air conditioning loads S _A and S _B are added to obtain a total value S _{AB. Then} , it is determined whether or not the total value S _{AB of the} air conditioning loads is a threshold value S _ref1 or more corresponding to the maximum value of the control capability of the outdoor unit 9. judge.

Here, if S _{AB ≤S ref1} , the A-chamber expansion valve control means 23 operates the expansion valve 5A according to the total value S _{AB of the} air conditioning load.
The B-chamber expansion valve control means 24 controls the opening degree of the expansion valve 5B, the compressor control means 25 performs capacity control operation of the compressor 1, and the outdoor fan control means 26 controls the outdoor heat exchanger. Drive 6 Since the control in the case of S _AB <S _ref1 has already been proposed and is publicly known, the description thereof will be omitted.

On the other hand, when S _AB > S _ref1 , the operation switching means 22 determines whether or not the indoor unit in the room A is preferentially operated by the priority order determining means 21, and the room A has the priority order 1 If it is the rank, a command for setting the expansion valve 5A to the normal operation opening is given to the A-chamber expansion valve control means 23, and at the same time, an operation command is given to the indoor fan control means 14 for the A-chamber, and conversely,
A command for closing the expansion valve 5B of the chamber is given to the B-chamber expansion valve control means 24, and an operation stop command is given to the indoor fan control means 14 of the B chamber. Further, the operation switching means 22 is a command to output the capacity corresponding to the air conditioning load S _A of the indoor unit 8A,
For example, the frequency command is added to the compressor control means 25. As a result, the operation with priority given to the room A is performed.

In this way, the detected room temperature T _{a of the} room A approaches the set room temperature T _s, and the air conditioning load corresponding to the difference corresponds to, for example, 1/3 of the maximum value of the control capacity of the outdoor unit 9. When the threshold value becomes equal to or lower than the threshold value S _ref2 to be controlled, the room B is preferentially operated this time. That is, the operation switching means 22 issues a command for setting the expansion valve 5B to the normal operation opening degree to the B-chamber expansion valve control means.
24, at the same time, an operation command is given to the indoor fan control means 14 of the B room, and conversely, a command to close the expansion valve 5A of the A room is given to the A room expansion valve control means 23 and the A room An operation stop command is given to the indoor fan control means 14 of. Further, the operation switching means 22 controls the air conditioning load S _{B of the} indoor unit 8B.
A command for outputting the capability corresponding to, for example, a frequency command is added to the compressor control means 25. Thereby, the operation in which the room B is prioritized is performed.

As a result, the detected room temperature T _{a of} room B approaches the set room temperature T _s, and the air conditioning load corresponding to the difference corresponds to, for example, 1/3 of the maximum value of the control capacity of the outdoor unit 9. When the threshold value becomes S _ref2 or less, operation switching means
The reference numeral 22 gives a normal operating opening command to both the A-room expansion valve control means 23 and 24, and also applies to the compressor control means 25 a frequency command for outputting the capacity corresponding to the air conditioning load S _AB at that time.

The overall operation of this embodiment will be described in more detail with reference to FIGS. 3 and 4. As shown in FIG. 3, the set room temperatures of the room A and the room B are equal to each other, T _s ,
It is assumed that the room temperature of the room A is T ₁ and the room temperature of the room B is T ₂ (> T ₁ ) at the operation start time t ₁ . For this reason, FIG.
As shown in the figure, since the air conditioning load S _A of the A chamber at time t ₁ is "15" in the air conditioning load S _B of the B chamber is "12", the load of the room A is greater than B chamber, priority Rank is A
Room 1st and room B 2nd, and the total value S
_AB becomes "27". On the other hand, if the maximum value of the capacity of the outdoor unit corresponding to the air conditioning load is “15”,
The threshold S _ref1 for preferential operation of one unit is set to "15".
Therefore, at time t ₁ , the indoor unit in the room A having the first priority is placed in the “operating” state, and the indoor unit in the room B having the second priority is placed in the “stop” state. As a result, the room temperature of the room A rises quickly as shown in FIG. 3, and the room temperature of the room B remains T ₂ . Then, at time t _{2, the} air conditioning load S
_A is a match to a threshold S _ref2 when the switching operation "5". At this time point, the total value S _AB of the air conditioning loads of the indoor units 10A and 10B is “17”, so only one unit is prioritized after time t ₂ . Therefore, the indoor unit of the room A is set to the “stop” state and the indoor unit of the room B is set to the “operation” state. As a result, the room temperature of the room A gradually decreases, as shown in FIG. 3, and the room temperature of the room B rapidly rises from time t ₂ .

Next, at time t ₃ , if the air conditioning load of the B room becomes "7" and the air conditioning load of the A room increases to "7}", the air conditioning of the indoor units 10A and 10B at this time point is performed. The total value S _{AB of the} loads is “14”, which is smaller than “15” which is the threshold S _ref1 for preferentially operating one vehicle. Therefore, after the time t _3, the indoor unit in the room A is in the “operating” state, and the indoor unit in the room B is also in the “operating” state.

FIG. 3 shows changes in the temperatures of the chambers A and B accompanying this operation together with the conventional operating method. According to the conventional method, the room temperature of the B chamber is set at time t ₅ . After reaching the temperature, the room temperature of the room A reaches the set temperature T _s at time t _6, but according to the present embodiment, both the room A and the room B reach the set temperature T _s at the time t ₄ . be able to.

FIG. 5 and FIG. 6 are flowcharts showing the processing procedure of the microprocessor for carrying out the above control, and the processing procedure will be outlined below.

FIG. 5 shows a processing procedure of the microprocessor which constitutes the indoor control unit 10A of the room A. The set room temperature T _SA is read in step 101, the detected room temperature T _aA is read in step 102, and then step The air conditioning load S _A is calculated at 103, and the calculated value is transmitted to the outdoor control unit 20 at step 104. Next, at step 105, it is judged whether or not there is a demand for capacity reduction from the outdoor control unit 20, and if there is a demand for capacity reduction, at step 106 the indoor fan is stopped as a measure for capacity reduction. In this way, when the indoor fan is stopped, it is determined in step 107 whether or not the capacity reduction command has been canceled, and if it has been canceled, in step 108 the steady operation of the indoor fan is executed. If it is determined in step 105 that the capacity reduction command is not given, step
At 108, the steady operation of the indoor fan is executed. Next, in step 109, it is determined whether or not a command to stop the operation of the air conditioner is given, and the processes in steps 101 to 109 are repeated until the command to stop the operation is given. Stop control.

The processing procedure of the microprocessor constituting the indoor control unit 10B of the room B is exactly the same as that of the room temperature T _SA to T _SB , the detected room temperature T _aA to T _aB , and the air conditioning load S.
The description is omitted because it is sufficient to replace _A with S _B.

FIG. 6 shows the processing procedure of the microprocessor constituting the outdoor control unit 20, and in step 201, the operation of the compressor and the outdoor fan is started. In step 202, the calculated load values S sent from the indoor control units 10A and 10B, respectively.
Read _A and S _B. In the next step 203, the air conditioning load S
Compare the magnitudes of _A and S _B , and set one with the largest air-conditioning load as the first priority operation priority and the other as the second priority operation priority.
Determine the rank. Subsequently, at step 204, the calculated values S _A and S _{B of the} air conditioning load are added to obtain a total value S _AB . Then, in step 205, the total value S _{AB of the} air conditioning load is compared with the threshold value S _{ref1 for} whether or not priority operation is performed. If S _AB ≤S _ref1 , the above steps 201 to 205 are repeated, and step 206 The subsequent priority operation processing is not executed.

On the contrary, when S _AB > S _ref1, it is determined in step 206 whether or not the indoor unit in the room A should be preferentially operated to execute the priority operation, and the room A is preferentially operated. In step 207, the indoor control unit issues a command to the indoor unit in the B room to perform the capacity reducing operation of the B room.
10B, and in step 208, the opening of the expansion valve connected to the heat exchanger in chamber B is closed. Next steps
At 209, it is determined whether the air conditioning load S A in the room _A has become equal to or less than the other threshold value S _ref2 described above. If it is less than S _ref2 , a capacity reduction command is given to the room B in step 210. Then, in step 211, the opening degree of the expansion valve connected to the heat exchanger in the B chamber is returned to the normal opening degree. Next, in step 212, it is determined whether or not there is an operation stop command for the air conditioner.
The process of step 206 is executed, and since the room A is not in the priority operation at that time, the processes of step 213 and thereafter are executed. Therefore, in step 213, a command for performing capacity reduction operation is sent to the indoor unit in the room A to the indoor control unit 10A, and in step 214, the opening degree of the expansion valve connected to the heat exchanger in the room A is transmitted. Close. In the next step 215, it is determined whether the air conditioning load S A of the room _A has become equal to or less than the other threshold value S _ref2 described above. If it is less than S _ref2 , the capacity for the room A is determined in step 216. The reduction command is released, and in step 217, the opening degree of the expansion valve connected to the heat exchanger in the chamber A is returned to the normal opening degree, and the process proceeds to step 212.

Thus, when the total value S _AB of the air conditioning loads of all the indoor units exceeds the threshold value S _ref1 corresponding to the maximum value of the capacity of the outdoor unit, only the indoor unit having the first priority is operated first, When the air conditioning load of this indoor unit falls below another threshold value S _ref2 , the priority is set to 2
It is possible to repeatedly control the switching operation to the second indoor unit until the total value S _AB of the air conditioning loads of all the indoor units falls below the threshold value S _ref1 .

In the above embodiment, the threshold value S _ref1 for preferentially operating the indoor unit is a value corresponding to the maximum control capacity of the outdoor control unit, but a value close to the upper limit of the control capacity may be used. The same control as described above is possible.
Further, although the threshold value S _ref2 for switching operation of the indoor unit is set to about 1/3 of the maximum value of the control capability of the outdoor control unit, the threshold value S _ref2 is temporarily set to 1 / th of the maximum value of the control capability of the outdoor control unit. Even if it is set to about 2, the control according to the above embodiment can be performed.

Further, in the above embodiment, it is assumed that the air conditioning load of one indoor unit to be preferentially operated matches the value corresponding to the maximum value of the control capability of the outdoor unit. When the indoor fan of is stopped and the expansion valve connected to it is closed, but the air conditioning load of the indoor unit with the first priority is smaller than the value corresponding to the maximum control capacity of the outdoor unit, ,
The maximum efficiency of the outdoor unit is controlled, the indoor fan of the indoor unit with the second highest priority is set to the minimum rotation speed, and the opening of the expansion valve connected to this indoor unit is throttled so that high efficiency can be achieved. Multi-room air conditioning becomes possible.

Furthermore, in the above-described embodiment, the case where two indoor units are connected to one outdoor unit has been illustrated, but the present invention is not limited to this, and three outdoor units are provided. even if the base or more indoor units are connected, the threshold S _{re f1} the total value of the air-conditioning loads of all the indoor units corresponding to the maximum value of the capacity of the outdoor unit
When the indoor unit with the highest priority is exceeded, only the first indoor unit is operated first, and when the air conditioning load of this indoor unit falls below another threshold value S _ref2 , the operation is switched to the next indoor unit with the priority. By repeating the above control until the total value of the air conditioning loads of all the indoor units falls below the threshold value S _{ref1, the} same effect as that of the above-described embodiment can be obtained.

By the way, in the above-mentioned embodiment, the priority order is determined by setting the one with a large air-conditioning load as the higher order, but it is expected that there will be a request to arbitrarily determine the priority operation order regardless of the size of the air-conditioning load. It In such a case,
As shown by the broken line in FIG. 1, the priority order external setting means 21
A is provided and operation switching means is used instead of the priority determination means 21.
It should be added to 22.

[0035]

As is apparent from the above description, according to the present invention, even when the total value of the air conditioning loads of a plurality of air conditioning target rooms exceeds the maximum value of the control capability of the outdoor unit, the size and cost are reduced. With the outdoor unit, it is possible to provide a control device for a multi-room air conditioner that enables the start-up of room temperature close to that of a large capacity outdoor unit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing detailed functions of a microprocessor included in each of the main elements of an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an embodiment of the present invention together with a refrigeration cycle system.

FIG. 3 illustrates the operation of an embodiment of the present invention.
A diagram showing the relationship between temperature and time.

FIG. 4 is a chart for explaining the operation of the embodiment of the present invention.

FIG. 5 is a flowchart showing a processing procedure of a microprocessor included in each of the main elements of the embodiment of the present invention.

FIG. 6 is a flowchart showing a processing procedure of a microprocessor included in each of the main elements of the embodiment of the present invention.

[Explanation of symbols]

 1 Compressor 3A, 3B Indoor heat exchanger 4A, 4B Indoor fan 5A, 5B Expansion valve 6 Outdoor heat exchanger 7 Outdoor fan 10A, 10B Indoor control unit 11 Room temperature setting means 12 Room temperature detecting means 13 Air conditioning load calculating means 14 Indoor fan Control means 20 Outdoor control section 21 Priority determination means 21A Priority external setting means 22 Operation switching means 23 A room expansion valve control means 24 B room expansion valve control means 25 Compressor control means 26 Outdoor fan control means

Claims (8)

[Claims] 1. A controller for a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit, room temperature setting means for setting the temperature of the room in which the indoor unit is installed, A room temperature detecting means for detecting the temperature of the indoor unit, an air conditioning load calculating means for calculating an air conditioning load for each indoor unit based on a difference between the set room temperature and the detected room temperature, and an air conditioning load for each indoor unit. And the priority determining means for determining the priority order for operating the indoor unit with a large air-conditioning load as a higher rank, and the calculated air-conditioning load, and the total value is the control capacity of the outdoor unit. When a predetermined value corresponding to the upper limit of the indoor unit is exceeded, the indoor unit having the first priority is operated at its required capacity, and the operating capacity of the indoor unit having the second priority or lower is determined. Multi-chamber control device for an air conditioner, wherein the operation switching means for operating in Hesi, further comprising a. 2. The operation switching means is operated so far when the air conditioning load of the indoor unit having the first priority is below a second predetermined value that is sufficiently smaller than the predetermined value. 2. The multi-room air conditioner according to claim 1, wherein the operating capacity of the indoor unit having the first priority is reduced, and the indoor unit having the second priority is operated with the required capacity. Control device. 3. The operation switching means operates all of the indoor units with a required capacity when the air conditioning loads of all the indoor units become equal to or lower than a second predetermined value. A control device for the multi-room air conditioner described. 4. The control device for a multi-room air conditioner according to claim 1, wherein the operation capacity is reduced by stopping the indoor fan and closing the expansion valve. 5. The control device for a multi-room air conditioner according to claim 1 or 2, wherein the operation capacity is reduced by operating an indoor fan at a minimum rotation speed and slightly reducing an expansion valve. . 6. The control device for a multi-room air conditioner according to claim 1, wherein the predetermined value corresponds to a maximum value of control capability of the outdoor unit. 7. The control device for a multi-room air conditioner according to claim 2, wherein the second predetermined value corresponds to a value that is half or less of a control capacity of the outdoor unit. 8. A priority order external setting means capable of arbitrarily setting a priority order for operating the indoor unit from outside, instead of the priority order setting means. A control device for a multi-room air conditioner as described above.