JPH06307723A - Multi-room type air conditioner - Google Patents

Abstract

PURPOSE:To execute a control of an outdoor-side blower which enables the control of a discharge pressure to be a prescribed value in a cooling circuit and shows an excellent responsiveness even in a transition period in the case when the state of a refrigeration cycle operation changes. CONSTITUTION:A discharge pressure detecting means 21 which detects a discharge pressure of a compressor 2 at prescribed time intervals, a storage means 26 which stores detected values in a plurality of times of the discharge pressure detecting means 21, a state-of-change computing means 25 which computes a deviation of the detected values in a plurality of times transmitted from the storage means 26 and the discharge pressure detecting means 21 from a target value and the state of change, and an outdoor-side blower control means 33 which determines an operation or a stoppage for a prescribed period of an outdoor-side blower 6 in a cooling circuit on the basis of the result of computation by the state-of-change computing means 25, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle control for a multi-room air conditioner, and more particularly to improving the accuracy of pressure control by an outdoor blower.

[0002]

2. Description of the Related Art As a conventional pressure control for a multi-room air conditioner, there is one that employs an outdoor blower control disclosed in, for example, Japanese Patent Laid-Open No. 3-156245.

The conventional multi-room air conditioner will be described below with reference to the drawings. FIG. 9 is a block diagram of an outdoor blower control of a conventional multi-room air conditioner.

In the figure, reference numeral 1 is an outdoor unit, which comprises a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor expansion valve 5, and outdoor blowers 6a, 6b, 6c. 7a, 7
Reference numeral b denotes an indoor unit, and indoor expansion valves 8a and 8b, respectively.
b, indoor side blowers 9a, 9b, indoor side heat exchanger 10a,
It is composed of 10b.

Further, the compressor 2, the four-way valve 3, the outdoor heat exchanger 4, the outdoor expansion valve 5, the indoor expansion valves 8a and 8b, and the indoor heat exchangers 10a and 10b are sequentially connected in an annular shape for refrigeration. It constitutes a cycle.

Reference numeral 21 is a discharge pressure detecting means for detecting the discharge pressure of the compressor 2 at regular time intervals, and 23 is the outdoor blowers 6a, 6 according to the discharge pressure detected by the discharge pressure detecting means 21.
It is a cooling room outside blower control means for controlling b and 6c.

Next, the operation will be described by taking the cooling operation as an example. The discharge pressure detection means 21 detects the discharge pressure at regular time intervals. The outdoor blower control means 22 is provided with a fan step as shown in (Table 1) in advance by a combination of operating or stopping the outdoor blowers 6a, 6b, 6c. If the discharge pressure is equal to or higher than a predetermined value, the fan step is performed. The amount of air is controlled by performing a process of raising one stage and lowering it by one stage if it is a predetermined value or less at a constant time interval to control the discharge pressure within a certain range.

[0008]

[Table 1]

[0009]

However, in the above-mentioned conventional structure, it is difficult to control the discharge pressure to a constant value even if the discharge pressure can be controlled within the constant range by the outdoor blower control.
When all the indoor units 7a and 7b connected to the pipe are in the cooling operation, if the suction pressure is controlled to be constant by the control of the compressor 2, there is little influence on the cooling capacity, but there is no problem. When performing the cooling / heating simultaneous operation, there is a drawback that the heating capacity fluctuates due to the fluctuation of the discharge pressure.

According to the present invention, the outdoor pressure can be controlled to a constant value by the outdoor air blower control in the cooling circuit, and the outdoor air exhibits excellent responsiveness even during the transition period when the refrigeration cycle operating state changes. A first object is to provide a multi-room air conditioner that controls a blower.

Further, in the above-mentioned conventional configuration, the suction pressure can be controlled within a fixed range by detecting the suction pressure in the heating circuit, but it is difficult to control the suction pressure to a fixed value, and all the pipes are connected. If the indoor unit of the unit is in heating operation, there is no problem as long as the discharge pressure is controlled to be constant by the control of the compressor, since it has little effect on the heating capacity. However, there is a drawback in that the cooling capacity fluctuates due to fluctuations in the.

According to the present invention, the outdoor side can control the suction pressure to a constant value by controlling the outdoor side blower in the heating circuit, and exhibits the excellent responsiveness even in the transition period when the refrigerating cycle operating state changes. A second object is to provide a multi-room air conditioner that controls a blower.

Further, in the above-mentioned conventional configuration, in order to perform the air volume control in the low speed region more finely in order to perform the proper capacity control during the cooling operation at the low outside air temperature and the heating operation at the high outside air temperature, the number of the blowers is required. There is a drawback in that the structure becomes complicated because a method such as increasing the number of components is required.

The present invention provides a multi-chamber air conditioner which can control the outside air blower so that the air flow can be reduced and the number of air blowers can be controlled more finely in a small air flow range than the conventional configuration. The third purpose is to provide.

Further, in the above-mentioned conventional configuration, the fan step N = 0 shown in (Table 1) is shown when the cooling load of the indoor unit is extremely small with respect to the outdoor unit capacity during the simultaneous heating / cooling operation in the cooling circuit.
However, even if the outdoor blower is stopped, the discharge pressure does not rise, the heating capacity of the indoor unit is not in heating operation, or the reliability of the compressor is impaired.

A fourth object of the present invention is to expand the region where the discharge pressure can be controlled by controlling the outdoor blower.

[0017]

In order to achieve the first object, a multi-room air conditioner of the present invention comprises a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, an outdoor blower. And an indoor side heat exchanger, an indoor side expansion valve, a plurality of indoor units consisting of an indoor side blower, the outdoor side expansion valve and the indoor side expansion valve pipe connection and the indoor side heat exchange It has a refrigeration cycle capable of simultaneous cooling and heating operation by connecting one end of the compressor to a suction side and a discharge side of the compressor by a branch unit, and has a discharge pressure of the compressor for a predetermined time. Discharge pressure detection means for detecting at intervals, storage means for storing and storing a plurality of detection values of the discharge pressure detection means, and a target based on a plurality of detection values transmitted from the storage means and the discharge pressure detection means Deviation and variation It has a change state calculation means for calculating the state, and an outdoor blower control means for determining whether to operate or stop the outdoor blower in the cooling circuit for a certain period of time based on the calculation result calculated by the change state calculation means. .

In order to achieve the second object, an outdoor unit including a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, an outdoor blower, an indoor heat exchanger, and an indoor expansion. A plurality of indoor units including a valve and an indoor blower, and the outdoor expansion valve and the indoor expansion valve are connected by piping, and one end of the indoor heat exchanger is connected to a suction side of the compressor by a branch unit and discharged. And a suction pressure detecting means for detecting suction pressure of the compressor at constant time intervals, and the suction pressure detecting means. Storage means for storing and storing a plurality of detection values of a plurality of times, change state calculation means for calculating a deviation and a change state with respect to a target value from a plurality of detection values transmitted from the storage means and the suction pressure detection means, The above Than it and an outdoor fan control means for determining the operating or stopping a certain period of the chamber outside air blower in the heating circuit by calculation result calculated by the state calculation unit.

In order to achieve the third object, the outdoor unit comprises a plurality of outdoor blowers and a plurality of outdoor blower control means corresponding to the outdoor blowers, and the outdoor blower control means is the outdoor blower control means. The outside blower is individually decided to operate or stop for a certain period of time.

Further, in order to achieve the fourth object, there is provided an outdoor expansion valve control means for controlling the opening / closing of the outdoor expansion valve in the cooling circuit according to the calculation result calculated by the change state calculation means.

[0021]

According to the present invention, the discharge pressure in the cooling circuit can be stabilized at the control target value by the above configuration. In addition, the next detection value is predicted based on the detection value of multiple times to decide whether to operate or stop the outdoor blower, so it shows excellent responsiveness even during the transition period when the refrigeration cycle operating state changes and protects. The operation of the device or the like can be eliminated.

Further, with the above configuration, the suction pressure in the heating circuit can be stabilized at the control target value.

Further, according to the above-mentioned configuration, the plurality of outdoor blowers are individually controlled based on one control law, so that the air volume can be reduced, and the number of air blowers is smaller than that of the conventional configuration. The control can be performed more finely.

Further, according to the above-mentioned structure, when the heating and cooling operations in the cooling circuit are simultaneously performed or when the cooling load of the indoor unit is extremely small with respect to the outdoor unit capacity, the outdoor expansion valve is throttled and the outdoor heat exchanger is cooled by the liquid refrigerant. By reducing the condensing capacity of the outdoor heat exchanger and increasing the discharge pressure by accumulating, the area where the discharge pressure can be controlled by the outdoor blower control can be expanded.

[0025]

EXAMPLE A first multi-room air conditioner according to the present invention will be described below.
Embodiments will be described with reference to the drawings. FIG. 1 is a block diagram of a first embodiment of a multi-room air conditioner according to the present invention. FIG. 2 is a flowchart showing the operation of the multi-room air conditioner of the same embodiment. In addition, the same reference numerals are given to the parts having the same configurations as those of the conventional one.

In FIG. 1, reference numeral 1 is an outdoor unit, which is composed of a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor expansion valve 5, and an outdoor blower 6. Reference numerals 7a and 7b are indoor units, and are configured by indoor expansion valves 8a and 8b, indoor blowers 9a and 9b, and indoor heat exchangers 10a and 10b, respectively.

Reference numerals 11a and 11b denote branch units, which are heating solenoid valves 12a and 12b and cooling solenoid valve 13, respectively.
a, 13b, and these solenoid valves 12a, 12
By switching b, 13a, 13b, one end of the indoor heat exchangers 10a, 10b is connected to either the suction side or the discharge side of the compressor 2 to enable simultaneous cooling and heating operation.

Reference numeral 21 denotes a discharge pressure detecting means for detecting the discharge pressure of the compressor 2 at regular time intervals, which is connected to the discharge pipe of the compressor 2 via a capillary tube. 25 is a change state calculation means,
The discharge pressure detection means 21 and a storage means 26 that stores and stores a plurality of detection values of the discharge pressure detection means 21 are electrically connected, and a plurality of detections transmitted from the storage means 26 and the discharge pressure detection means 21. The deviation and change state from the target value are calculated from the value.

Reference numeral 33 is an outdoor blower control means, which is electrically connected to the change state calculation means 25 and is used to change the change state calculation means 2.
Based on the calculation result calculated by 5, the operation or stop of the outdoor blower 6 in the cooling circuit for a certain period is determined.

The operation of the multi-room air conditioner configured as described above will be described below with reference to the flowchart of FIG.

The discharge pressure detecting means 21 detects the discharge pressure at regular time intervals (STEP 1). The detected pressure data P (t) is transmitted to the storage unit 26 and stored as the pressure data of the present time t, and at the same time, the pressure data P (t-1) of the last time t-1 and the pressure data of the time t-2 before the last time. P (t-
2) and transmitted to the change state calculation means 25 (ST
EP2).

The change state calculating means 25 outputs a calculation result U (t) in which the deviation of the discharge pressure with respect to the target value, the gradient of the discharge pressure change, and the magnitude of the discharge pressure change rate are taken into consideration, based on the above three data. Yes (STEP 3). Calculation result U (t)
Is transmitted to the outdoor blower control means 33, and a judgment is made based on the rule shown in (Table 2) to determine whether to operate or stop the outdoor blower 6 for a fixed time until the next detection (ST.
EP4).

Pressure data P stored in the storage means 26
(T) and P (t-1) are respectively P (t-1) and P (t
-2) (STEP 5). By repeating the above operation, the discharge pressure can be controlled to a constant value.

It is possible to suppress the pressure fluctuation due to the operation or stop by using a microcomputer capable of performing the processing of each STEP at high speed and reducing the interval of a constant time.

[0035]

[Table 2]

Next, a second embodiment of the multi-room air conditioner according to the present invention will be described with reference to the drawings. The same components as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be given. The description is omitted. FIG. 3 shows a second multi-chamber air conditioner according to the present invention.
2 is a block diagram of an embodiment of FIG. FIG. 4 is a flowchart showing the operation of the multi-room air conditioner according to the same embodiment.

In FIG. 3, reference numeral 22 is a suction pressure detecting means for detecting the suction pressure of the compressor 2 at regular time intervals, which is connected to the suction pipe of the compressor 2 via a capillary tube. Reference numeral 35 is a change state calculation means, which is a suction pressure detection means 22 and a storage means 36 for storing and storing a plurality of detection values of the suction pressure detection means 22.
A deviation and a change state with respect to a target value are calculated from a plurality of detection values transmitted from the storage means 36 and the suction pressure detection means 22.

The outdoor blower control means 34 is electrically connected to the change state calculation means 35, and the change state calculation means 3 is provided.
Based on the calculation result calculated by 5, the operation or stop of the outdoor blower 6 in the heating circuit for a certain period is determined.

The operation of the multi-room air conditioner configured as described above will be described below with reference to the flowchart of FIG.

The suction pressure detecting means 22 detects the suction pressure at regular time intervals (STEP 1). The detected pressure data P (t) is transmitted to the storage unit 36 and stored as the pressure data of the present time t, and at the same time, the pressure data P (t-1) of the previous time t-1 and the pressure data of the time t-2 before the previous time. P (t-
2) and transmitted to the change state calculation means 35 (ST
EP2).

The change state calculating means 35 outputs a calculation result U (t) based on the above three data in consideration of the deviation of the discharge pressure with respect to the target value, the gradient of the discharge pressure change, and the magnitude of the discharge pressure change rate. Yes (STEP 3). Calculation result U (t)
Is transmitted to the outdoor blower control means 34, and the determination is made according to the rule shown in (Table 3) to determine whether to operate or stop the outdoor blower 6 for a fixed time until the next detection (ST.
EP4).

Pressure data P stored in the storage means 36
(T) and P (t-1) are respectively P (t-1) and P (t
-2) (STEP 5). By repeating the above operation, the suction pressure can be controlled to a constant value.

[0043]

[Table 3]

Next, a third embodiment of the multi-room air conditioner according to the present invention will be described with reference to the drawings. The same components as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be given. The description is omitted. FIG. 5 is a third multi-room air conditioner according to the present invention.
2 is a block diagram of an embodiment of FIG. FIG. 6 is a flowchart showing the operation of the multi-room air conditioner according to the embodiment.

In FIG. 5, 6a and 6b are outdoor blowers for blowing air to the outdoor heat exchanger 4, 33a is a first outdoor blower control stage corresponding to the outdoor blower 6a, and the outdoor blower 6a. For each, it is decided to operate or stop for a certain period. 33b is a second corresponding to the outdoor blower 6b
The outdoor air blower control unit determines whether the outdoor air blower 6b is individually operated or stopped for a certain period.

The operation of the multi-room air conditioner configured as described above will be described below with reference to the flowchart of FIG. 6 by taking the cooling operation as an example. The operation up to STEP 3 is the same as that of the multi-room air conditioner according to the first embodiment, and the description thereof is omitted. The calculation result U (t) is transmitted to the first and second outdoor fan control means 33a and 33b, respectively.
The size is judged according to the rules shown in (Table 4), and the operation or stop of the outdoor fans 6a and 6b for a fixed time until the next detection is individually decided (STEP 4).

STEP 5 has the same operation as that of the multi-room air conditioner according to the first embodiment, and a description thereof will be omitted. By repeating the above operation, when the change in the discharge pressure is small, the same control as in the first embodiment is performed only by the outdoor blower 6a, and when the discharge pressure suddenly changes, the outdoor blower 6b. Therefore, even if the required air volume during the cooling operation at low outside temperature is small, the air volume can be controlled appropriately.

[0048]

[Table 4]

Next, a fourth embodiment of the multi-room air conditioner according to the present invention will be described with reference to the drawings. The same components as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be given. The description is omitted. FIG. 7 shows a fourth multi-chamber air conditioner according to the present invention.
2 is a block diagram of an embodiment of FIG. FIG. 8 is a flowchart showing the operation of the multi-room air conditioner according to the embodiment.
In FIG. 7, reference numeral 27 is an outdoor expansion valve control means for controlling opening / closing of the outdoor expansion valve 5 in the cooling circuit based on the calculation result calculated by the change state calculation means 25.

The operation of the multi-room air conditioner configured as described above will be described below with reference to the flowchart of FIG. The operation up to STEP 3 is the same as that of the multi-room air conditioner according to the first embodiment, and the description thereof is omitted. The calculation result U (t) is transmitted to the outdoor blower control means 33 and the outdoor expansion valve control means 27, respectively, and the outdoor blower 6 for a fixed time until the next detection is performed by judging the magnitude according to the rule shown in (Table 5). It is determined whether or not to operate or to open or close the outdoor expansion valve 5 (STEP 4).

STEP 5 has the same operation as the multi-room air conditioner according to the first embodiment, and will not be described. By repeating the above operation, when the discharge pressure is extremely small with respect to the target value, the outdoor expansion valve 5 is throttled, and the liquid refrigerant is accumulated in the outdoor heat exchanger 4, whereby the outdoor heat exchanger 4 is closed. It is possible to expand the area where the discharge pressure can be controlled by the outdoor blower 6 by lowering the condensation capacity of the air conditioner and increasing the discharge pressure, and the cooling load of the indoor unit and the cooling load of the indoor unit can increase the outdoor unit capacity. Even when it is extremely small, proper capacity control can be performed.

[0052]

[Table 5]

[0053]

As described above, the multi-chamber air conditioner of the present invention includes a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve,
An outdoor unit consisting of an outdoor blower, an indoor heat exchanger, an indoor expansion valve, a plurality of indoor units consisting of an indoor blower, the outdoor expansion valve and the indoor expansion valve are pipe-connected and the room A refrigeration cycle that enables simultaneous cooling and heating operation by connecting one end of the inner heat exchanger to a suction side and a discharge side of the compressor by a branch unit, and has a discharge pressure of the compressor. Discharge pressure detecting means for detecting the discharge pressure at a constant time interval, storage means for storing and storing a plurality of detection values of the discharge pressure detecting means, and a plurality of detections transmitted from the storage means and the discharge pressure detecting means. The change state calculating means for calculating the deviation and the change state from the target value based on the value, and the operation result of the outside state blower in the cooling circuit for a certain period based on the calculation result calculated by the change state calculating means. Can be stabilized because it has an outdoor blower control means for determining a stop, the discharge pressure at the cooling circuit to the control target value. Further, based on the detection value of multiple times to predict the next detection value to determine the operation or stop of the outdoor blower, showing excellent responsiveness even in the transition period when the refrigeration cycle operating state changes, It is possible to eliminate the operation of the protection device and the like.

Also, a compressor, a four-way valve, an outdoor heat exchanger,
An outdoor expansion valve, an outdoor unit consisting of an outdoor blower, an indoor heat exchanger, an indoor expansion valve, a plurality of indoor units consisting of an indoor blower, the outdoor expansion valve and the indoor expansion valve pipe A refrigeration cycle that enables simultaneous cooling and heating operation by connecting one end of the indoor side heat exchanger by a branch unit so as to be switchable between a suction side and a discharge side of the compressor, Suction pressure detection means for detecting the suction pressure of the compressor at fixed time intervals, storage means for storing and storing a plurality of detection values of the suction pressure detection means, and transmission from the storage means and the suction pressure detection means. A change state calculating means for calculating a deviation and a change state from a target value based on a plurality of detection values, and one of the outdoor blower in the heating circuit based on the calculation result calculated by the change state calculating means. Because it has an outdoor blower control means for determining the operation or stop of the period, it is possible to stabilize the suction pressure in the heating circuit to the control target value.

Further, the outdoor unit comprises a plurality of outdoor blowers and a plurality of outdoor blower control units corresponding to the outdoor blowers, and the outdoor blower control units individually operate the outdoor blowers for a certain period of time. Or decide to stop, so
It is possible to reduce the air volume, and more precise control can be performed in the small air volume range with a smaller number of fans than the conventional configuration.

Further, since there is an outdoor expansion valve control means for controlling the opening / closing of the outdoor expansion valve in the cooling circuit based on the calculation result calculated by the change state calculation means, it is possible to perform simultaneous cooling / heating operation in the cooling circuit, or an indoor unit. When the cooling load of the outdoor heat exchanger is extremely small compared to the outdoor unit capacity, the outdoor expansion valve is throttled and liquid refrigerant is stored in the outdoor heat exchanger to reduce the condensation capacity of the outdoor heat exchanger and increase the discharge pressure. As a result, it is possible to provide an excellent multi-room air conditioner that can expand the region where the discharge pressure can be controlled and can always operate the refrigeration cycle in an efficient state.

[Brief description of drawings]

FIG. 1 is a control block diagram of a multi-room air conditioner that is a first embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the multi-room air conditioner of the same embodiment.

FIG. 3 is a control block diagram of a multi-room air conditioner that is a second embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of the multi-room air conditioner of the same embodiment.

FIG. 5 is a control block diagram of a multi-room air conditioner that is a third embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the multi-room air conditioner of the same embodiment.

FIG. 7 is a control block diagram of a multi-room air conditioner that is a fourth embodiment of the present invention.

FIG. 8 is a flowchart showing the operation of the multi-room air conditioner of the same embodiment.

FIG. 9 is a control block diagram of a conventional air conditioner.

[Explanation of symbols]

 1 outdoor unit 2 compressor 3 four-way valve 4 outdoor heat exchanger 5 outdoor expansion valve 6, 6a, 6b outdoor blower 7a, 7b indoor unit 8a, 8b indoor expansion valve 9a, 9b indoor blower 10a, 10b chamber Inner heat exchanger 11a, 11b Branch unit 12a, 12b Heating solenoid valve 13a, 13b Cooling solenoid valve 21 Discharge pressure detection means 22 Suction pressure detection means 25, 35 Change state calculation means 26, 36 Storage means 27 Outdoor expansion valve Control means 33, 34 Outdoor air blower control means 33a First outdoor air blower control means 33b Second outdoor air blower control means

Claims (4)

[Claims] 1. An outdoor unit including a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve, and an outdoor blower, and a plurality of indoor units including an indoor heat exchanger, an indoor expansion valve, and an indoor blower. Machine, the outdoor side expansion valve and the indoor side expansion valve are connected by piping, and one end of the indoor side heat exchanger is connected by a branch unit so as to be switchable between the suction side and the discharge side of the compressor. A refrigeration cycle capable of simultaneous cooling and heating operation, wherein a discharge pressure detection means for detecting the discharge pressure of the compressor at fixed time intervals and a plurality of detection values of the discharge pressure detection means are stored and stored. Storage means, a change state calculation means for calculating a deviation and a change state with respect to a target value from a plurality of detection values transmitted from the storage means and the discharge pressure detection means, and a performance state calculated by the change state calculation means. A multi-room air conditioner comprising: an outdoor blower control means that determines whether to operate or stop the outdoor blower in the cooling circuit for a certain period of time based on the calculation result. 2. An outdoor unit comprising a compressor, a four-way valve, an outdoor heat exchanger, an outdoor expansion valve and an outdoor blower, and a plurality of indoor rooms comprising an indoor heat exchanger, an indoor expansion valve and an indoor blower. Machine, the outdoor side expansion valve and the indoor side expansion valve are connected by piping, and one end of the indoor side heat exchanger is connected by a branch unit so as to be switchable between the suction side and the discharge side of the compressor. A refrigeration cycle capable of simultaneous cooling and heating operation is provided, and suction pressure detection means for detecting the suction pressure of the compressor at fixed time intervals and a plurality of detection values of the suction pressure detection means are stored and stored. Storing means, a change state calculating means for calculating a deviation and a change state with respect to a target value from a plurality of detection values transmitted from the storage means and the suction pressure detecting means, and a performance calculated by the change state calculating means. A multi-room air conditioner comprising: an outdoor blower control unit that determines whether to operate or stop the outdoor blower in a heating circuit for a certain period of time based on a calculation result. 3. The outdoor unit includes a plurality of outdoor blowers and a plurality of outdoor blower control units corresponding to the outdoor blowers, and the outdoor blower control units individually operate the outdoor blowers for a certain period of time. Alternatively, the stop is determined, and the multi-room air conditioner according to claim 1 or 2. 4. The multi-room air conditioner according to claim 1, further comprising an outdoor expansion valve control means for controlling the opening / closing of the outdoor expansion valve in the cooling circuit based on the calculation result calculated by the change state calculation means.