WO2018154853A1 - Air conditioning system - Google Patents

Abstract

Provided is an air conditioning system equipped with one or a plurality of air conditioners that, during normal conditions, operate by receiving power supply from a normal power source and that, during a power outage of the normal power source, operate by receiving power supply from an emergency power source, wherein: the air conditioning system is equipped with an operation control unit for controlling the operation of the one or plurality of air conditioners, a power outage determination unit for detecting a power outage of the normal power source, and an operation command unit for executing, when a power outage has been detected by the power outage determination unit, power-limiting operation in which the power used by the one or plurality of air conditioners is limited on the basis of a preset upper limit power; and the operation control unit controls the operation of the one or plurality of air conditioners such that the overall power used by the one or plurality of air conditioners does not exceed the upper limit power when the power-limiting operation is being executed by the operation command unit.

Description

Air conditioning system

The present invention relates to an air conditioning system that suppresses power consumption when an emergency power supply is used.

In general, an air conditioning system such as a multi air conditioning system for buildings is connected to an outdoor unit that is a heat source unit arranged outside a building and a plurality of indoor units arranged inside the building, and is usually supplied from a commercial power source. Operation such as cooling or heating is performed by electric power. Such an air conditioning system further includes an uninterruptible power supply or an emergency generator as an emergency power supply, and operates with power from the emergency power supply when the commercial power supply that is a normal power supply stops. Yes (see, for example, Patent Document 1).

In Patent Document 1, the compressor, the indoor unit blower, the means for detecting the commercial power supply cutoff, and the capacity of the compressor rotation speed and / or the indoor unit blower air volume are suppressed when the commercial power supply cutoff is detected. And an air conditioning system comprising the means. The air conditioning system of Patent Document 1 has a suppression operation mode in which, for example, the compressor is operated at the lowest frequency and the air volume of the indoor unit blower is suppressed, and the suppression operation mode is performed during a power failure of the commercial power supply. It is the composition which becomes.

JP 2007-24431 A

However, in the air conditioning system of Patent Document 1, the frequency of the compressor and the air volume of the indoor unit blower are set regardless of the power supplied from the emergency power supply. For this reason, for example, when the compressor is set to the lowest frequency, the air conditioning system can only exhibit a minimum air conditioning capacity even though there is a surplus up to the upper limit of the supplied power. In some cases, the ability was insufficient.

The present invention has been made in order to solve the above-described problems. When the power supply is interrupted and power is supplied from the emergency power supply, the maximum air conditioning is achieved even when the power supply is suppressed. The purpose is to provide an air conditioning system for operation.

An air conditioning system according to the present invention operates normally with power supplied from a normal power source, and includes one or a plurality of air conditioners that operate with power supplied from an emergency power source during a power failure of the normal power source. In the harmony system, when a power failure is detected by the operation control unit that controls the operation of one or a plurality of the air conditioners, the power failure determination unit that detects a power failure of the regular power supply, and the power failure determination unit, An operation command unit that performs an electric power limiting operation that limits electric power used by the plurality of air conditioners based on a preset upper limit electric power, and the operation control unit is configured to limit the electric power by the operation command unit. When the operation is being performed, the operation of the one or more air conditioners is performed within a range where the total power used by the one or more air conditioners is equal to or less than the upper limit power. It is Gosuru thing.

According to the air conditioning system according to the present invention, the power used by one or a plurality of air conditioners is limited based on the preset upper limit power at the time of power failure of the regular power supply. That is, the air conditioning system according to the present invention has a configuration in which the power is limited by the upper limit power, and the operation control unit can control the operation within the range of the upper limit power. Therefore, the operation efficiency at the time of using the emergency power supply is improved as compared with the conventional suppression operation mode. For example, when the upper limit power is the power supplied from the emergency power supply, the air conditioning system can be operated with the maximum air conditioning capability within the range of the power supplied.

It is a circuit diagram which shows the circuit structure of the air conditioner of the air conditioning system which concerns on Embodiment 1 of this invention. It is a block diagram which shows schematic structure of the air conditioning system which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the function structure of the air conditioning system which concerns on Embodiment 1 of this invention. It is a flowchart figure which shows control of the air conditioning system which concerns on Embodiment 1 of this invention. It is a flowchart figure which shows control of the electric power limiting operation at the time of the independent operation of the air conditioning system which concerns on Embodiment 1 of this invention. It is a flowchart figure which shows control of the defrost operation at the time of the electric power restriction | limiting operation | movement of the air conditioning system which concerns on Embodiment 2 of this invention.

Hereinafter, the air conditioning system 100 of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
1 is a circuit diagram showing a circuit configuration of an air conditioner of an air conditioning system according to Embodiment 1 of the present invention. The air conditioner 1 will be described based on FIG. The air conditioner 1 is used as, for example, an air conditioner that heats or cools a target space. The air conditioner 1 is normally operated by electric power supplied from an ordinary power source such as a commercial power source. However, when the electric power supply from the ordinary power source is interrupted, electric power is supplied from an emergency power source. The emergency power source refers to, for example, an uninterruptible device or an emergency generator.

<Configuration of air conditioner 1>
The air conditioner 1 includes an outdoor unit 10 and two indoor units 50a and 50b. The air conditioner 1 has a refrigeration cycle for circulating a refrigerant, and each of the indoor units 50a and 50b can select a cooling operation mode or a heating operation mode as an operation mode. Specifically, the air conditioner 1 can set the operation mode of each of the indoor units 50a and 50b to the cooling operation mode or the heating operation mode by the flow path switching device 13 mounted on the outdoor unit 10.

The outdoor unit 10 and the indoor units 50 a and 50 b are connected by a refrigerant pipe 4 and a refrigerant pipe 5. FIG. 1 shows an example in which two indoor units 50a and 50b are connected in parallel to one outdoor unit 10, but the number of outdoor units 10 and indoor units 50 is the same. Is not particularly limited to this.

In the following description, when it is not necessary to distinguish between the indoor unit 50a and the indoor unit 50b, each of the indoor unit 50a and the indoor unit 50b will be described as the indoor unit 50. In addition, the components mounted in the indoor unit 50a and the indoor unit 50b are also illustrated by adding “a” and “b” at the end of each symbol. "And" b "are omitted.

(Outdoor unit 10)
The outdoor unit 10 is mainly installed outdoors, and has a function of supplying cold or warm heat to the indoor unit 50. The outdoor unit 10 includes a compressor 11, a check valve 12, a flow path switching device 13, an outdoor unit heat exchanger 14, an accumulator 16, and the like. The outdoor unit 10 is equipped with an outdoor unit blower 15.

The compressor 11 compresses the refrigerant flowing in through the accumulator 16 and discharges it as a high-temperature and high-pressure gas refrigerant. The compressor 11 can be configured by, for example, a rotary compressor, a scroll compressor, a screw compressor, or a reciprocating compressor. Moreover, the compressor 11 is good to comprise with the capacity | capacitance-controllable inverter compressor.

The check valve 12 is provided on the discharge side of the compressor 11 and allows the refrigerant to flow in only one direction.

The flow path switching device 13 is provided on the discharge side of the compressor 11 via the check valve 12, and switches the refrigerant flow between the cooling operation mode and the heating operation mode. The flow path switching device 13 can be composed of, for example, a two-way valve or a combination of three-way valves, or a four-way valve. During the cooling operation, the flow path switching device 13 connects the discharge side of the compressor 11 and the outdoor unit heat exchanger 14, and the refrigerant discharged from the compressor 11 is sent to the outdoor unit heat exchanger 14. On the other hand, at the time of heating operation, the flow path switching device 13 connects the discharge side of the compressor 11 and the refrigerant pipe 4, and the refrigerant discharged from the compressor 11 is sent to the indoor unit 50 via the refrigerant pipe 4. In addition, when the air conditioner 1 is a cooling only machine or a heating only machine, it is not necessary to provide the flow path switching device 13.

The outdoor unit heat exchanger 14 acts as an evaporator during heating operation, and acts as a condenser during cooling operation, and between the heat exchange fluid such as air supplied from a fluid transfer device such as the outdoor unit blower 15 and the refrigerant. Heat exchange. The outdoor unit heat exchanger 14 is, for example, a fin and tube heat exchanger, a microchannel heat exchanger, a shell and tube heat exchanger, a heat pipe heat exchanger, a double tube heat exchanger, or It can be composed of a plate heat exchanger or the like. In the first embodiment, the case where the outdoor unit heat exchanger 14 is a fin-and-tube heat exchanger will be described as an example.

The outdoor unit blower 15 is an example of a fluid transfer device, and supplies air to the outdoor unit heat exchanger 14. The outdoor unit blower 15 can be composed of, for example, a propeller fan having a plurality of blades. The outdoor unit blower 15 may be installed anywhere as long as it is installed in a place where air can be supplied to the outdoor unit heat exchanger 14. In addition, the fluid conveyance apparatus according to the type of the outdoor unit heat exchanger 14 may be selected. For example, when the heat exchange fluid is water, brine, or the like, the air conditioner 1 may be equipped with, for example, a pump instead of the outdoor unit blower 15.

The accumulator 16 is provided on the suction side of the compressor 11 and stores excess refrigerant due to a difference between the heating operation and the cooling operation, excess refrigerant due to a transient change in operation, or excess refrigerant generated due to load conditions. is there. The transitional change in operation refers to, for example, a case where the number of operating indoor units 50 changes. The accumulator 16 separates the liquid refrigerant and the gas refrigerant and supplies only the gas refrigerant to the compressor 11.

The outdoor unit 10 is further equipped with a control device 70 that performs overall control of the air conditioner 1. Each actuator (drive component) is connected to the control device 70, and the control device 70 controls the operation of each actuator. Examples of the actuator include the compressor 11, the flow path switching device 13, the outdoor unit blower 15, a throttle device 52 and an indoor unit blower 53, which will be described later. Further, the control device 70 is configured to detect a power failure of the regular power supply and transmit a detection signal to a communicable device such as a centralized management controller 80 (see FIG. 2) described later.

The control device 70 controls the operation of each actuator based on detection values from various sensors (not shown) (hereinafter referred to as a sensor group 60). As the sensor group 60, for example, a pressure sensor that is provided on the discharge side of the compressor 11 and detects the pressure of refrigerant discharged from the compressor 11, and a temperature sensor that is installed in each indoor unit 50 and detects the temperature. Etc. are included. The control device 70 may be configured by hardware such as a circuit device, or may be configured by a microcomputer or the like.

In addition, although the case where the control apparatus 70 is mounted in the outdoor unit 10 is illustrated in FIG. 1 as an example, the mounting location of the control apparatus 70 is not particularly limited. Furthermore, the indoor unit 50 may be provided with a control device, and the control device of the indoor unit 50 and the control device 70 may be connected to be communicable. In this case, an instruction from a remote controller (not shown) is input to the control device 70 via the control device of the indoor unit 50.

(Indoor unit 50)
The indoor unit 50 is installed indoors or the like, for example, and has a function of cooling or heating the air-conditioning target space by the cold or warm heat supplied from the outdoor unit 10. Each indoor unit 50 includes an indoor unit heat exchanger 51, an expansion device 52, an indoor unit blower 53, and the like.

The indoor unit heat exchanger 51 acts as a condenser during the heating operation, and acts as an evaporator during the cooling operation. The indoor unit heat exchanger 51 performs heat exchange between a heat exchange fluid such as air supplied from a fluid transfer device such as the indoor unit blower 53 and the refrigerant, and supplies air to the air-conditioning target space. Produce air. The indoor unit heat exchanger 51 is, for example, a fin and tube heat exchanger, a microchannel heat exchanger, a shell and tube heat exchanger, a heat pipe heat exchanger, a double pipe heat exchanger, or It can be composed of a plate heat exchanger or the like. In the first embodiment, the case where the indoor unit heat exchanger 51 is a fin-and-tube heat exchanger will be described as an example.

The indoor unit blower 53 is an example of a fluid transfer device, and supplies air to the indoor unit heat exchanger 51. The indoor unit blower 53 can be composed of, for example, a propeller fan having a plurality of blades. The indoor unit blower 53 may be disposed anywhere as long as it is installed in a place where air can be supplied to the indoor unit heat exchanger 51. Moreover, what is necessary is just to select a fluid conveying apparatus according to the type of the indoor unit heat exchanger 51. For example, when the heat exchange fluid is water or brine, a pump is mounted on the indoor unit 50 instead of the indoor unit blower 53 as a fluid transfer device.

The expansion device 52 expands and depressurizes the refrigerant that has passed through the indoor unit heat exchanger 51 or the outdoor unit heat exchanger 14. In FIG. 1, the expansion device 52 is provided between the outdoor unit heat exchanger 14 and each indoor unit heat exchanger 51. The expansion device 52 may be constituted by, for example, an electric expansion valve that can adjust the flow rate of the refrigerant. As the expansion device 52, a mechanical expansion valve using a diaphragm as a pressure receiving portion, a capillary tube, or the like may be used instead of using an electric expansion valve.

<Operation mode executed by the air conditioner 1>
Next, the operation mode executed by the air conditioner 1 will be described together with the flow of the refrigerant. The air conditioner 1 is configured such that the indoor unit 50 can perform a cooling operation or a heating operation based on an instruction from the indoor unit 50, for example. In Embodiment 1, the air conditioner 1 can execute the same operation of the cooling operation or the heating operation in all of the connected indoor units 50a and 50b.

(Cooling operation mode)
First, the cooling operation mode performed by the air conditioner 1 will be described. In FIG. 1, the refrigerant flow in the cooling operation mode is indicated by broken-line arrows. Hereinafter, the cooling operation mode of the air conditioner 1 will be described by taking as an example a case where the heat exchange fluid is air and the heat exchange fluid is a refrigerant.

When the air conditioner 1 executes the cooling operation mode, the outdoor unit 10 causes the flow path of the refrigerant discharged from the compressor 11 to flow into the indoor unit heat exchanger 51 via the outdoor unit heat exchanger 14. Thus, the flow path switching device 13 performs switching.

In the compressor 11, the low-temperature and low-pressure refrigerant is compressed and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the outdoor unit heat exchanger 14 via the check valve 12 and the flow path switching device 13. The refrigerant that has flowed into the outdoor unit heat exchanger 14 is heat-exchanged with the air supplied by the outdoor unit blower 15, and becomes a high-temperature and high-pressure liquid refrigerant that flows out of the outdoor unit heat exchanger 14.

The high-temperature and high-pressure liquid refrigerant that has flowed out of the outdoor unit heat exchanger 14 flows into the indoor unit 50 through the refrigerant pipe 5. The high-temperature and high-pressure liquid refrigerant flowing into the indoor unit 50 is converted into a low-temperature and low-pressure liquid refrigerant or a two-phase refrigerant by the expansion device 52 provided in the indoor unit 50 and flows into the indoor unit heat exchanger 51. The refrigerant that has flowed into the indoor unit heat exchanger 51 is heat-exchanged with the air supplied by the indoor unit blower 53 to become a low-temperature and low-pressure gas refrigerant and flows out of the indoor unit heat exchanger 51. As the refrigerant absorbs heat from the air in the indoor unit heat exchanger 51, the room that is the air-conditioning target space is cooled.

The refrigerant that has flowed out of the indoor unit heat exchanger 51 passes through the refrigerant pipe 4 and flows into the outdoor unit 10. The refrigerant that has flowed into the outdoor unit 10 is again sucked into the compressor 11 via the flow path switching device 13 and the accumulator 16. Thereafter, the above cycle is repeated.

(Heating operation mode)
Next, the heating operation mode performed by the air conditioner 1 will be described. In FIG. 1, the flow of the refrigerant in the heating operation mode is indicated by a solid line arrow. Hereinafter, the heating operation mode of the air conditioner 1 will be described by taking as an example a case where the heat exchange fluid is air and the heat exchange fluid is a refrigerant.

When the air conditioner 1 executes the heating operation mode, the outdoor unit 10 passes the flow path of the refrigerant discharged from the compressor 11 to the indoor unit heat exchanger 51 without passing through the outdoor unit heat exchanger 14. It switches by the flow-path switching apparatus 13 so that it may flow in.

In the compressor 11, the low-temperature and low-pressure refrigerant is compressed and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the indoor unit heat exchanger 51 via the check valve 12 and the flow path switching device 13. The refrigerant that has flowed into the indoor unit heat exchanger 51 is heat-exchanged with the air supplied by the indoor unit blower 53 and becomes a high-temperature and high-pressure liquid refrigerant that flows out of the indoor unit heat exchanger 51. In the indoor unit heat exchanger 51, the refrigerant radiates heat to the air, thereby heating the room.

The high-temperature and high-pressure liquid refrigerant that has flowed out of the indoor unit heat exchanger 51 becomes a low-temperature and low-pressure liquid refrigerant or a two-phase refrigerant by the expansion device 52 provided in each indoor unit 50, and enters the outdoor unit heat exchanger 14 of the outdoor unit 10. Inflow. The refrigerant that has flowed into the outdoor unit heat exchanger 14 is heat-exchanged with the air supplied by the outdoor unit blower 15, and becomes a low-temperature and low-pressure gas refrigerant that flows out of the outdoor unit heat exchanger 14.

The refrigerant that has flowed out of the outdoor unit heat exchanger 14 is again sucked into the compressor 11 via the flow path switching device 13 and the accumulator 16. Thereafter, the above cycle is repeated.

<Configuration of the air conditioning system 100>
FIG. 2 is a block diagram showing a schematic configuration of the air-conditioning system according to Embodiment 1 of the present invention. The air conditioning system 100 includes one or a plurality of the air conditioners 1 described above, a centralized management controller 80, and the like. Here, the case where the air conditioning system 100 includes a plurality of air conditioners 1A, 1B, 1C will be described. Hereinafter, when it is not necessary to particularly distinguish the air conditioner 1A, the air conditioner 1B, and the air conditioner 1C, each of the air conditioner 1A, the air conditioner 1B, and the air conditioner 1C is referred to as the air conditioner 1. explain. Further, the components mounted in the air conditioner 1A, the air conditioner 1B, and the air conditioner 1C will also be described by omitting the alphabet at the end of the reference unless otherwise distinguished. The centralized management controller 80 is a control device that manages the plurality of air conditioners 1A, 1B, and 1C. In FIG. 2, a case where three air conditioners 1A, 1B, 1C each including two indoor units 50 and one outdoor unit 10 are connected in parallel to one centralized controller 80. Although shown in the example, the number of connected air conditioners 1 and indoor units 50 is not particularly limited to this.

A plurality of air conditioners 1 are connected to the central control controller 80 so that they can communicate with each other by communication wiring or wirelessly. Specifically, a plurality of control devices 70 a, 70 b and 70 c are connected to the centralized management controller 80. The centralized management controller 80 acquires information from the plurality of outdoor units 10a, 10b, 10c and the plurality of indoor units 50a, 50b, 50c, 50d, 50e, 50f via the plurality of control devices 70a, 70b, 70c, I manage. Moreover, the centralized management controller 80 can transmit the operation command regarding control of the air conditioner 1 to the control apparatus 70 in an emergency, and can make an operation command carry out with priority.

FIG. 3 is a functional block diagram showing a functional configuration of the air-conditioning system according to Embodiment 1 of the present invention. The functions of the centralized management controller 80 and the control device 70 will be described with reference to FIG. In FIG. 3, only the centralized management controller 80 and the control device 70a of the air conditioner 1A are shown. However, the control device 70b and the control device 70c also have a centralized management controller 80 as in the control device 70a. And connected.

The control device 70 a includes a power failure determination unit 71 and an operation control unit 72. The power failure determination unit 71 detects a power failure of the regular power supply. For example, the power failure determination unit 71 is configured to constantly monitor the input power from the regular power source and detect a power failure by detecting a phase failure of the input power. The power failure determination unit 71 transmits a power failure signal to the centralized management controller 80 when detecting a power failure of the regular power supply. Moreover, the power failure determination part 71 transmits the reset signal which is a reset signal to the centralized management controller 80, when the input power supply from a regular power supply returns from a power failure.

In the normal operation mode, the operation control unit 72 controls each actuator of the air conditioner 1A based on information input from the remote controller, information acquired from the sensor group 60, and the like. The operation control unit 72 switches the drive frequency of the compressor 11, the switching of the flow path switching device 13, the rotation speed of the outdoor unit blower 15, the opening degree of the expansion device 52 of each indoor unit 50, and the rotation number of the indoor unit blower 53. Control etc. In addition, the operation control unit 72 transmits information on the indoor unit 50 and the outdoor unit 10 to the centralized management controller 80 and receives an operation command from the centralized management controller 80. Specifically, the operation control unit 72 transmits information related to the operation and air conditioning setting of each indoor unit 50, control information of the outdoor unit 10, and the like to the centralized management controller 80. When the operation control unit 72 receives an operation command from the centralized management controller 80, the operation control unit 72 controls the air conditioner 1A based on the received operation command.

The central management controller 80 has an information management unit 81, an operation unit 82, an operation command unit 83, and the like. The information management unit 81 manages information on each outdoor unit 10 and each indoor unit 50 acquired via each control device 70a, 70b, 70c. The information on the outdoor unit 10 includes, for example, control information of the actuator, and the information on the indoor unit 50 includes, for example, information such as an operation mode, an operation state such as operation or stop, and a set temperature. The information management unit 81 can transmit such information collectively or individually. Further, the information management unit 81 manages the power information of the emergency power supply and the priority information for each air conditioner 1. The power information includes, for example, set power Ps set in advance as power that can be supplied from the emergency power supply to the air conditioning system 100, the amount of power that can be allocated to the air conditioning system 100, and the like. Moreover, a priority is a priority which continues a driving | operation at the time of a power failure of a common power source. The priority may be set in advance from the operation unit 82 or the like at the time of installation or the like, or set by the operation command unit 83 based on operation information or the like during operation of each air conditioner 1. May be.

The operation unit 82 is input with commands or settings by an administrator or the like of the air conditioning system 100, and includes, for example, a touch panel having a liquid crystal screen or a display unit and a keyboard. The input setting is reflected in the information management unit 81, and the input command is executed by the operation command unit 83 as necessary.

The operation command unit 83 manages the operation of the plurality of air conditioners 1A, 1B, and 1C connected to the centralized management controller 80. In the normal operation mode, the operation of each air conditioner 1 is controlled by each control device 70 based on the input from the remote controller, the set information, and the information from the sensor group 60 and the like. The operation command unit 83 receives the power failure signal from the power failure determination unit 71, and switches the operation mode from the normal operation mode to the power limited operation mode when the normal power supply has a power failure. The power limited operation mode is an operation mode in which the power used by the connected air conditioner 1 is limited based on a preset set power Ps. During the power limited operation, the operation command unit 83 transmits an operation command to the control device 70 as necessary, and causes the operation control unit 72 to control the air conditioner 1 based on the operation command. Specifically, the operation command unit 83 sends one operation control unit 72 to the operation control unit 72 within a range in which the total power use Pu of one or more connected air conditioners 1A, 1B, 1C is equal to or less than the set power Ps. Alternatively, the operation of the plurality of air conditioners 1 is controlled. The operation command unit 83 ends the power limited operation when receiving the return signal.

<Power limited operation>
FIG. 4 is a flowchart showing control of the air-conditioning system according to Embodiment 1 of the present invention. Hereinafter, control performed by the centralized management controller 80 and the control device 70 in the air conditioning system 100 will be described.

When the air conditioning system 100 starts operation, normal operation is performed (step ST101). The power failure determination unit 71 monitors the input power from the normal power source, and determines whether a power failure of the normal power source is detected during normal operation (step ST102). When a power failure is detected by the power failure determination unit 71 (step ST102: YES), a power failure signal is transmitted to the centralized management controller 80. When the central management controller 80 receives the power failure signal, the operation command unit 83 starts the power limited operation (step ST103). On the other hand, when a power failure is not detected by power failure determination unit 71 (step ST102: NO), normal operation is continued (step ST101), and the power failure determination of step ST102 is repeated every predetermined time.

In the power limited operation, the operation command unit 83 limits the power used by the air conditioning system 100 to be within the power supplied by the emergency power source. First, the operation command unit 83 performs power determination for determining whether the used power Pu is greater than the set power Ps (step ST104). At this time, the operation command unit 83 transmits a request signal to notify each control device 70a, 70b, 70c of the power of the air conditioner 1. When the control device 70 receives the request signal, the operation control unit 72 calculates the amount of power from the operating frequency of the compressor 11 and the rotational speed of the outdoor unit blower 15 and notifies the centralized management controller 80 of the calculated amount of power. To do. The operation command unit 83 totals the notified power amounts of the air conditioners 1A, 1B, and 1C, and compares the used power Pu obtained by totaling with the set power Ps set in the information management unit 81. To do.

When it is determined that the used electric power Pu is equal to or lower than the set electric power Ps in the electric power determination (step ST104: NO), the operation command unit 83 does not need to suppress the operation of the air conditioner 1; The operating state of the air conditioners 1A, 1B, 1C is maintained. On the other hand, when it is determined that the used power Pu is greater than the set power Ps (step ST104: YES), the operation command unit 83 further determines whether there are a plurality of air conditioners 1 that are in operation. (Step ST105). Then, when only one air conditioner 1 is in operation (step ST105: NO), the operation command unit 83 starts the power limited operation during the single operation (step ST201).

On the other hand, when the plurality of air conditioners 1 are in operation (step ST105: YES), the operation command unit 83 has the lowest priority among the plurality of air conditioners 1 in operation. Is stopped (step ST106). At this time, the operation command unit 83 refers to the priority of each air conditioner 1 stored in the information management unit 81, and issues an operation command to stop the operation of the air conditioner 1 for which the lowest priority is set. To the control device 70. Specifically, when priority “high”, “medium”, or “low” is set for the air conditioner 1A, the air conditioner 1B, and the air conditioner 1C, respectively, the priority “low” is set. An operation command for stopping the operation of the air conditioner 1C is transmitted. Then, the controller 70c of the air conditioner 1C stops each actuator of the air conditioner 1C based on the operation command. On the other hand, the operation of the air conditioner 1A and the air conditioner 1B is continued.

After step ST106 or when the current operation state of each air conditioner 1A, 1B, 1C is maintained by the power determination in step ST104, a power failure recovery determination is performed (step ST107). The power failure determination unit 71 determines that the power failure has been restored when the input power from the utility power returns (step ST107: YES), and transmits a return signal to the centralized management controller 80. Operation command unit 83 ends the power limited operation when a return signal is received from power failure determination unit 71 (step ST108). Thereafter, normal operation is performed (step ST101). On the other hand, when the return signal is not transmitted from the power failure determination unit 71 (step ST107: NO), the operation command unit 83 performs the power determination of step ST104 again. The processing from step ST104 to step ST107 is repeated until the central control controller 80 receives a return signal. For example, the total used power Pu2 counted in the second power determination (step ST104) is smaller than the used power Pu1 at the previous power determination because the air conditioner 1C is stopped. In addition, even after the air conditioner 1C is stopped, if the used power Pu2 exceeds the set power Ps, the air conditioner for which the second lowest priority is set in the second step ST106. 1B is stopped.

<Power limited operation during single operation>
FIG. 5 is a flowchart showing the control of the power limiting operation during the single operation of the air-conditioning system according to Embodiment 1 of the present invention. Hereinafter, the power limit operation when only one air conditioner 1A is in operation will be described. The power limiting operation during the single operation is to limit the power consumption of the air conditioner 1 during the operation so as to be equal to or less than the set power Ps.

When the power limited operation at the time of the single operation is started (step ST201), the operation command unit 83 calculates the frequency Fs of the compressor 11 and the rotation speed Ns of the outdoor unit fan 15 when operating with the preset set power Ps. (Step ST202). Then, the operation command unit 83 sets the calculated frequency Fs as the upper limit frequency of the compressor 11 and sets the calculated rotation speed Ns as the upper limit rotation speed of the outdoor unit blower 15 for the operating air conditioner 1A. (Step ST203). At this time, the operation command unit 83 reflects the set upper limit frequency and upper limit rotation number in the information management unit 81 and transmits the operation command to the control device 70a. Then, the operation control unit 72 controls the compressor 11 and the outdoor unit blower 15 of the air conditioner 1A during operation based on the operation command with the frequency Fs and the rotation speed Ns as upper limits. When the setting in step ST203 is completed, a power failure recovery determination is performed (step ST204). The power failure determination unit 71 determines that the power failure has been restored when the input power from the utility power returns (step ST204: YES), and transmits a return signal to the centralized management controller 80. The operation command unit 83 ends the power limited operation when receiving a return signal from the power failure determination unit 71 (step ST205). Thereafter, normal operation is performed (step ST101). On the other hand, when the return signal is not received from the power failure determination unit 71 (step ST204: NO), the power limited operation is continued based on the set upper limit frequency and upper limit rotation speed. Thereafter, the power failure recovery determination in step ST204 is repeated until the centralized management controller 80 receives a recovery signal.

As described above, in the first embodiment, the air conditioning system 100 includes the operation control unit 72, the power failure determination unit 71, and the operation command unit 83. The operation command unit 83 limits the power used by one or more air conditioners 1A, 1B, and 1C based on the upper limit power (set power Ps) when a power failure is detected by the power failure determination unit 71. Carry out driving. In the operation control unit 72, when the power instruction operation is performed by the operation command unit 83, the total power use Pu of one or a plurality of the air conditioners 1A, 1B, 1C is equal to or less than the upper limit power (set power Ps). The operation of one or more air conditioners 1 is controlled within a range.

As a result, the overall power consumption is limited based on the preset upper limit power (set power Ps) at the time of a power failure of the utility power supply, but the operation control unit 72 controls the operation within the range of the upper limit power. Can do. For example, when the supply power of the emergency power supply is set as the upper limit power, the air conditioning system 100 can be operated with the maximum air conditioning capability in the range of the supply power. Therefore, as compared with the suppression operation mode set as in the prior art, the degree of freedom of control when using the emergency power supply is increased, and the overall power usage Pu is limited to the upper limit power (set power Ps) or less. It is possible to avoid stopping the operation of the entire system. That is, the air conditioning system 100 can continue the operation commensurate with the set power Ps even when the supplied power is limited.

Further, the power failure determination unit 71 detects a power failure when a phase failure of the regular power supply is detected. Thus, since the abnormal state of the input power supply is detected at an early stage, the air conditioning system 100 can perform stable operation by performing maintenance or switching to an emergency power supply.

The air conditioning system 100 further includes a centralized management controller 80 that manages one or a plurality of air conditioners 1A, 1B, and 1C, and the operation command unit 83 is included in the centralized management controller 80. Thus, the air conditioning system 100 can perform power limited operation or transmit an operation command using the operation information of one or more air conditioners 1A, 1B, and 1C managed by the centralized management controller 80. it can.

Further, the operation command unit 83 is a case where a power failure is detected by the power failure determination unit 71, and the total power use Pu of one or a plurality of air conditioners 1A, 1B, 1C is higher than the upper limit power (set power Ps). If it is larger, carry out power limited operation.

As a result, the air conditioning system 100 continues operation by limiting the total power consumption Pu when the power supply is insufficient during a power failure of the normal power supply, while the total power consumption Pu becomes the set power Ps. For example, a normal operation can be performed and a highly efficient operation can be performed.

In addition, when the plurality of air conditioners 1A, 1B, and 1C are in operation during the power limited operation, the operation command unit 83 gives the operation control unit 72 a low priority among the plurality of air conditioners 1 in operation. The operation of the air conditioner (for example, the air conditioner 1C) is stopped.

Thus, when a plurality of air conditioners 1A, 1B, and 1C are operating during the power limited operation, the total power usage Pu is limited based on the priority. Therefore, the air conditioning system 100 can continue the operation even in an emergency for an air conditioner (for example, the air conditioner 1A) to be prioritized.

Further, each of the one or more air conditioners 1A, 1B, 1C has a compressor 11 and an outdoor unit blower 15. The operation control unit 72 controls the compressor 11 and the outdoor unit blower 15. The operation command unit 83 sets the upper limit power (for example, set power) when only one air conditioner (the air conditioner 1A) among the one or more air conditioners 1A, 1B, 1C is operating in the power limited operation. The frequency of the compressor 11 and the rotational speed of the outdoor unit fan 15 at Ps) are calculated. Then, the operation command unit 83 causes the operation control unit 72 to control the compressor 11 and the outdoor unit blower 15 of the operating air conditioner 1A with the calculated frequency Fs and rotation speed Ns as upper limits.

Thus, the operation control unit 72 can arbitrarily control the compressor 11 and the outdoor unit blower 15 with the frequency Fs and the rotation speed Ns at the set power Ps as upper limits in the power limited operation. Therefore, compared with the suppression operation mode which operates at the compressor frequency and the rotation speed of the indoor unit blower set as in the prior art, the air conditioning system 100 is high within the set range even when the emergency power supply is used. Efficient air conditioning can be provided.

The embodiment of the present invention is not limited to the above embodiment, and various changes can be made. For example, in the first embodiment, the plurality of air conditioners 1A, 1B, and 1C are each provided with the control device 70, and the centralized management controller 80 is described as managing the plurality of air conditioners 1A, 1B, and 1C. It is not limited to such a configuration. When the air conditioning system 100 is configured by one air conditioner 1, the control device 70 may have the function of the centralized management controller 80.

Further, the refrigeration cycle is not limited to the circuit configuration of FIG. 1. For example, the outdoor unit 10 may have a mechanism for switching the refrigerant flow for each indoor unit 50.

Further, the central management controller 80 may be provided with a part or all of the functions of the control device 70, or the control device 70 may be provided with a part or all of the functions of the central management controller 80. For example, a configuration in which a power failure or power failure recovery is determined by the centralized management controller 80 instead of the control device 70 may be employed.

In step ST104, the operation command unit 83 transmits a request signal to notify each control device 70 of the electric power used by the air conditioner 1. However, already acquired information may be used. The operation command unit 83 may be configured to calculate the power usage of each air conditioner 1 and the total power usage Pu based on the latest operation information stored in the information management unit 81.

Embodiment 2. FIG.
FIG. 6 is a flowchart showing the control of the defrosting operation during the power limited operation of the air-conditioning system according to Embodiment 2 of the present invention. In Embodiment 2, each air conditioner 1A, 1B, 1C performs a defrosting operation in addition to the heating operation and the cooling operation described above. Each of the air conditioners 1A, 1B, and 1C further includes a refrigerant temperature sensor as the sensor group 60. The refrigerant temperature sensor is disposed in the outdoor unit heat exchanger 14 and detects the temperature of the refrigerant flowing through the outdoor unit heat exchanger 14. In the air conditioner 1, when the amount of frost formation in the outdoor unit heat exchanger 14 increases during the heating operation mode, a defrosting operation for melting frost is performed.

The operation control unit 72 of the control device 70 performs control so as to start the defrosting operation when the temperature of the refrigerant detected by the refrigerant temperature sensor becomes equal to or lower than a set temperature, for example. Moreover, the operation control part 72 is controlled to complete | finish a defrost operation and restart a heating operation, when the set defrost time Tdef passes from the start of a defrost operation. In the defrosting operation, the operation control unit 72 performs control so that the compressor 11 is operated at the set defrosting frequency Fdef. Note that the start condition of the defrosting operation is not limited to the determination based on the temperature of the refrigerant. For example, a low pressure sensor may be disposed on the suction side of the compressor 11 and the defrosting operation may be started when the refrigerant pressure detected by the low pressure sensor becomes equal to or lower than a set pressure.

Here, the defrosting time Tdef is an execution time per defrosting operation. The defrost frequency Fdef and the defrost time Tdef are determined by the amount of heat necessary for the defrosting of the outdoor unit heat exchanger 14 of the own unit in the control devices 70a, 70b, 70c of the air conditioners 1A, 1B, 1C. Set values are stored in advance. Hereinafter, it is assumed that the control device 70a of the air conditioner 1A stores the set frequency Fdef1 as the set value of the defrost frequency Fdef and the set defrost time Tdef1 as the set value of the defrost time Tdef.

The centralized management controller 80 acquires the set values of the defrost frequency Fdef and the defrost time Tdef described above, and these acquired set values are managed by the information management unit 81 as information on the outdoor unit 10.

(Defrosting operation)
When the control device 70 performs the defrosting operation in the air conditioner 1, the flow switching device 13 is switched to the flow channel in the cooling operation mode, and the outdoor unit blower 15 and the indoor unit blower 53 are controlled to stop. Further, the control device 70 controls the compressor 11 to operate at the set defrost frequency Fdef. For example, at the normal time, the defrost frequency Fdef is set to the maximum frequency of the compressor 11 in order to melt frost in a short time.

During the defrosting operation, the compressor 11 compresses the low-temperature and low-pressure refrigerant and discharges it as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows into the outdoor unit heat exchanger 14 via the check valve 12 and the flow path switching device 13. The refrigerant that has flowed into the outdoor unit heat exchanger 14 melts frost by radiating heat to become a liquid refrigerant and flows out of the outdoor unit heat exchanger 14.

The liquid refrigerant flowing out of the outdoor unit heat exchanger 14 flows into the indoor unit 50 through the refrigerant pipe 5. The liquid refrigerant flowing into the indoor unit 50 passes through the expansion device 52 provided in the indoor unit 50 and flows into the indoor unit heat exchanger 51. The refrigerant that has flowed into the indoor unit heat exchanger 51 evaporates due to the heat of the piping, and part or all of the refrigerant becomes a gas refrigerant and flows out of the indoor unit heat exchanger 51. The refrigerant that has flowed out of the indoor unit heat exchanger 51 flows into the outdoor unit 10 through the refrigerant pipe 4. The refrigerant that has flowed into the outdoor unit 10 is again sucked into the compressor 11 via the flow path switching device 13 and the accumulator 16. Thereafter, the above cycle is repeated until the defrosting operation is completed.

By the way, in the conventional air conditioning system, the power consumption is suppressed by uniformly setting the compressor to the lowest frequency. Further, in the power suppression operation during the single operation of the first embodiment, the upper limit of the operation frequency of the compressor 11 is limited to the frequency Fs. Therefore, in the power suppression operation mode in which the compressor 11 is driven at a frequency lower than the normal defrost frequency Fdef, the frost is sufficiently melted even if the defrost operation of the normal defrost time Tdef is performed. May not be possible.

Therefore, in the second embodiment, when the defrosting operation is performed in the power limited operation, the defrosting time Tdef necessary for the defrosting of the outdoor unit heat exchanger 14 is calculated, and the calculated defrosting time Tdef is removed. A frost operation is performed. Hereinafter, as an example, the control in the case where the defrosting operation is performed when the power limiting operation during the single operation of FIG. 5 is performed will be described based on FIG. 6. Here, it is assumed that only the air conditioner 1A is in operation, and the air conditioner 1A is performing the heating operation while the power failure recovery determination in step ST204 of FIG. 5 is repeated. When the start condition of the defrosting operation is established in the air conditioner 1A and the operation control unit 72 executes the defrosting operation, the control of FIG. 6 is started.

First, the operation command unit 83 calculates the defrost frequency Fs2 of the compressor 11 when operating with the preset set power Ps (step ST301). And the operation instruction | command part 83 calculates the required defrost time Ts in case the defrost operation is performed by driving the compressor 11 with the calculated defrost frequency Fs2 in the air conditioner 1A (step ST302).

Here, a method for calculating the necessary defrosting time Ts will be described. The amount of heat Q required for defrosting of the outdoor unit heat exchanger 14 of the air conditioner 1A is expressed by the following formula 1 using the set defrosting time Tdef1 set in the normal defrosting operation.

[Equation 1]
Q = Gr × Tdef1 × ΔH (Formula 1)
Gr: Refrigerant flow rate ΔH: Enthalpy difference before and after heat exchange The refrigerant flow rate Gr in Equation 1 above is expressed by Equation 2 below using the set frequency Fdef1 set in the normal defrosting operation.

[Equation 2]
Gr = V × ηv × Fdef1 × ρ (Formula 2)
V: Displacement amount of the compressor 11 ηv: Volumetric efficiency ρ: Refrigerant density That is, in order to obtain the heat quantity Q necessary for defrosting of the outdoor unit heat exchanger 14 of the air conditioner 1A, the defrost frequency Fdef and the defrosting are performed. The product with time Tdef should just be constant. That is, the relationship of the following formula 3 is established.

[Equation 3]
Fdef1 × Tdef1 = Fs2 × Ts (Formula 3)
Therefore, the necessary defrosting time Ts when the compressor 11 is driven at the defrosting frequency Fs2 during the defrosting operation in the power limiting operation is calculated by the following equation 4.

[Equation 4]
Ts = (Fdef1 × Tdef1) / Fs2 (Formula 4)
After step ST302, the operation command unit 83 transmits an operation command to the control device 70a of the air conditioner 1A, and the operation control unit 72 of the control device 70a performs the defrosting operation based on the operation command received from the operation command unit 83. Is executed (step ST303). At this time, the operation control unit 72 switches the flow path switching device 13 to the flow path in the cooling operation mode and controls the outdoor unit blower 15 to stop, and the compressor 11 is calculated based on the operation command. Control is performed to operate at the frost frequency Fs2. And the operation control part 72 complete | finishes a defrost operation, when the required defrost time Ts passes from the start of a defrost operation. At this time, the operation control unit 72 controls the flow path switching device 13 to switch to the flow path in the heating operation mode and to resume the heating operation.

And during the heating operation, the operation control unit 72 controls the operation frequency of the compressor 11 with the frequency Fs as the upper limit, and controls the rotation speed of the outdoor unit heat exchanger 14 with the rotation speed Ns as the upper limit. Thereafter, while the power failure recovery determination in step ST204 in FIG. 5 is repeated, the operation control unit 72 interrupts the heating operation when the start condition of the defrosting operation is satisfied, and executes the defrosting operation in step ST303 in FIG. .

As described above, in the configuration in which the defrosting operation is performed during the power limited operation during the single operation, step ST301 may be omitted, and the necessary defrosting time at the upper limit frequency Fs may be calculated in step ST302. .

Moreover, although the electric power limiting operation at the time of an independent operation was demonstrated, also when a plurality of air conditioners (for example, the air conditioner 1A and the air conditioner 1B) are operating at the time of the electric power limiting operation, FIG. 5 and FIG. By the control, an efficient operation can be carried out with the set power Ps or less. In this case, for example, the operation command unit 83 assigns the power that can be used to the plurality of air conditioners 1A and 1B in which the operation is maintained so that the total used power Pu is equal to or less than the set power Ps. It is good to allocate to each of the harmony machines 1A and 1B. Then, in step ST202 of FIG. 5, the operation command unit 83 calculates the frequency Fs of the compressor 11 with the allocated power and the rotation speed Ns of the outdoor unit blower 15, and in step ST301 of FIG. The defrost frequency Fs2 of the compressor 11 with electric power is calculated. Here, the power allocated to each of the air conditioners 1A and 1B may be determined by dividing the set power Ps by the number of the plurality of air conditioners 1A and 1B in which the operation is maintained. With such a configuration, even when the plurality of air conditioners 1A and 1B are operating in the power limited operation, the cooling operation, the heating operation, and the defrosting operation are efficiently performed within the range of the electric power allocated to each. can do.

As described above, in the second embodiment, when the power control operation is performed by the operation command unit 83, the operation control unit 72 uses the entire power consumption Pu of one or more air conditioners 1A, 1B, 1C. The defrosting operation is controlled within a range in which the power becomes equal to or lower than the upper limit power (set power Ps). As a result, even when the defrosting operation is performed in the operating air conditioner 1, the operation control unit 72 keeps the total power consumption Pu below the upper limit power (set power Ps) and is within the range of the upper limit power. The operation can be controlled with.

Also, the operation control unit 72 controls the compressor 11 to operate at a preset set frequency Fdef1 during the defrosting operation. The operation command unit 83 defrosts the compressor 11 at the upper limit power (set power Ps) when only the air conditioner 1A is operating in the power limited operation and the air conditioner 1A executes the defrosting operation. The frequency Fs2 is calculated. Then, the operation command unit 83 causes the operation control unit 72 to control the compressor 11 to operate at the calculated defrost frequency Fs2. As a result, the defrosting operation is performed by driving the compressor 11 with the upper limit power within the range of the power supplied in the power limiting operation. The defrosting of the outdoor unit heat exchanger 14 can be efficiently performed within the range.

Also, the operation control unit 72 performs control so that the defrosting operation for the set defrosting time Tdef1 is executed and terminated. When only one air conditioner 1A is in operation in the power limited operation, the operation command unit 83 instructs the operation control unit 72 to set the defrosting time Tdef1 when the air conditioner 1A performs the defrosting operation. Control is performed to execute a defrosting operation with a long required defrosting time Ts. Thereby, since the defrosting operation is executed longer than usual at the time of the power limiting operation, even if the operation frequency of the compressor 11 is limited in the power limiting operation, the frost of the outdoor unit heat exchanger 14 is melted, A decrease in heat exchange efficiency due to frost formation can be suppressed.

Further, the operation command unit 83 calculates the necessary defrost time Ts by dividing the product of the set frequency Fdef1 and the set defrost time Tdef1 by the calculated defrost frequency Fs2. Thereby, the calorie | heat amount Q required for the defrosting of the outdoor unit heat exchanger 14 can be ensured, and frost can be melt | dissolved reliably.

1 (1A, 1B, 1C) air conditioner, 4 refrigerant pipe, 5 refrigerant pipe, 10 (10a, 10b, 10c) outdoor unit, 11 compressor, 12 check valve, 13 flow path switching device, 14 outdoor unit heat Exchanger, 15 outdoor unit blower, 16 accumulator, 50 (50a, 50b, 50c, 50d, 50e, 50f) indoor unit, 51 (51a, 51b) indoor unit heat exchanger, 52 (52a, 52b) throttle device, 53 (53a, 53b) Indoor unit blower, 60 sensors, 70 (70a, 70b, 70c) control device, 71 power failure determination unit, 72 operation control unit, 80 centralized management controller, 81 information management unit, 82 operation unit, 83 operation Command section, 100 air conditioning system, Fdef defrost frequency, Fdef1 set frequency, Fs frequency, Fs2 calculated Defrost frequency, Ns rotational speed, Ps set power, Pu, Pu1, Pu2 use power, Q heat, Tdef defrosting time, Tdef1 set defrost time, Ts necessary defrosting time.

Claims (11)

1. In an air conditioning system including one or a plurality of air conditioners that are normally operated by receiving power supply from an ordinary power source and that are operated by receiving power supply from an emergency power source in the event of a power failure of the ordinary power source,
   An operation control unit that controls the operation of the one or more air conditioners;
   A power failure determination unit that detects a power failure of the utility power supply;
   An operation command unit that performs a power limit operation that limits power used by one or a plurality of the air conditioners based on a preset upper limit power when a power failure is detected by the power failure determination unit. ,
   When the power control operation is performed by the operation command unit, the operation control unit is configured so that one or a plurality of the air conditioners are used in a range where the total power consumption of the one or a plurality of the air conditioners is equal to or less than the upper limit power. An air conditioning system that controls the operation of the air conditioner.
2. The air conditioning system according to claim 1, wherein the power failure determination unit detects a power failure when an open phase of the regular power source is detected.
3. A central control controller for managing one or a plurality of the air conditioners;
   The air conditioning system according to claim 1 or 2, wherein the operation command unit is included in the centralized controller.
4. 4. The power operation unit according to claim 1, wherein the operation command unit performs the power limited operation when a power outage is detected by the power outage determination unit and the overall power consumption is larger than the upper limit power. The air conditioning system according to one item.
5. When the plurality of air conditioners are in operation in the power limited operation, the operation command unit has a lower priority set in the operation control unit among the plurality of air conditioners in operation. The air conditioning system according to any one of claims 1 to 4, wherein the overall power consumption is limited by stopping the operation of the air conditioner.
6. Each of the one or more air conditioners has a compressor that compresses the refrigerant,
   The air conditioning system according to any one of claims 1 to 5, wherein the operation control unit controls the compressor.
7. Each of the one or more air conditioners has an outdoor unit blower,
   The operation control unit controls the outdoor unit blower,
   In the power limited operation, when only one of the air conditioners is operating, the operation command unit is configured to determine the frequency of the compressor at the upper limit power and the outdoor unit. The rotational speed of the blower is calculated, and the operation control unit is configured to control the compressor and the outdoor unit blower of the air conditioner during operation with the calculated frequency and the rotational speed as upper limits. Air conditioning system.
8. The operation control unit is configured so that when the power command operation is performed by the operation command unit, the entire power usage of the one or more air conditioners is less than or equal to the upper limit power. The air conditioning system according to claim 6 or 7, wherein a defrosting operation of the air conditioner is controlled.
9. Each of the one or more air conditioners includes a flow path switching device that switches a flow path of the refrigerant from the compressor, and an outdoor unit heat exchanger that exchanges heat between the refrigerant and the heat exchange fluid.
   The operation control unit controls the flow path switching device to connect the discharge side of the compressor to the outdoor unit heat exchanger during the defrosting operation, and sets the compressor at a preset frequency. Control to drive,
   In the power limited operation, the operation command unit is configured such that only one of the air conditioners is operating, and the operating air conditioner performs the defrosting operation. The air conditioning system according to claim 8, wherein a defrost frequency of the compressor at the upper limit power is calculated, and the operation control unit is controlled to operate the compressor at the calculated defrost frequency. .
10. The operation control unit performs control so as to execute a predetermined defrosting time set in advance and the defrosting operation to be finished,
    In the power limited operation, the operation command unit is configured such that only one of the air conditioners is operating, and the operating air conditioner performs the defrosting operation. The air conditioning system according to claim 9, wherein the operation control unit is controlled to execute the defrost operation for a required defrost time longer than the set defrost time.
11. The air conditioning system according to claim 10, wherein the operation command unit calculates the necessary defrost time by dividing the product of the set frequency and the set defrost time by the calculated defrost frequency.

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