Air conditioning system and control method

Abstract

An air conditioning system according to an embodiment comprises an internal conditioner control unit and an external conditioner control unit. If an operating capacity of an external conditioner is equal to or greater than a first threshold and an operating capacity of an internal conditioner can be increased, the internal conditioner control unit increases the operating capacity of the internal conditioner, and if the operating capacity of the external conditioner is less than a second threshold that is smaller than the first threshold and the operating capacity of the internal conditioner can be reduced, the internal conditioner control unit reduces the operating capacity of the internal conditioner. If the operating capacity of the internal conditioner is equal to or greater than a third threshold and the operating capacity of the external conditioner can be increased, the external conditioner control unit increases the operating capacity of the external conditioner, and if the operating capacity of the internal conditioner is less than a fourth threshold that is smaller than the third threshold and the operating capacity of the external conditioner can be reduced, the external conditioner control unit reduces the operating capacity of the external conditioner.

Description

Air conditioning system and control method

[0001] This application claims priority to Japanese Patent Application No. 2022-192823, filed December 1, 2022, the contents of which are incorporated herein by reference.

[0002] In the prior art, the linked control of indoor and outdoor air-conditioning units was aimed at reducing the amount of power consumed, and involved comparing COP (Coefficient of Performance) and power consumption.

[0003] Japanese Patent No. 6414354

[0004] This requires the use of equipment and meters capable of measuring the amount of electricity used, which increases the cost of installing them. Furthermore, when simply comparing COP, it is often the case that either the indoor or outdoor air-conditioning unit is operating at a high load, or that the operating time is uneven. As a result, parts of the equipment operating at a high load are more likely to break down, or the maintenance interval for the equipment operating at a high load may be shortened. As such, conventional technology has had the problem of increasing the running costs of the air-conditioning system due to the need to replace parts due to breakdowns and shortened maintenance intervals.

[0005] The problem to be solved by the present invention is to provide an air conditioning system and a control method that reduce the running costs of the air conditioning system.

[0006] An air conditioning system according to an embodiment includes an indoor air conditioning unit control unit and an outdoor air conditioning unit control unit. The indoor air conditioning unit control unit increases the operating capacity of the indoor air conditioning unit when the operating capacity of the outdoor air conditioning unit is equal to or greater than a first threshold and the operating capacity of the indoor air conditioning unit can be increased, and decreases the operating capacity of the indoor air conditioning unit when the operating capacity of the outdoor air conditioning unit is less than a second threshold that is smaller than the first threshold and the operating capacity of the indoor air conditioning unit can be decreased. The outdoor air conditioning unit control unit increases the operating capacity of the outdoor air conditioning unit when the operating capacity of the indoor air conditioning unit is equal to or greater than a third threshold and the operating capacity of the outdoor air conditioning unit can be increased, and decreases the operating capacity of the outdoor air conditioning unit when the operating capacity of the indoor air conditioning unit is less than a fourth threshold that is smaller than the third threshold and the operating capacity of the outdoor air conditioning unit can be decreased.

[0007] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

[0008] Hereinafter, an air conditioning system and a control method according to an embodiment will be described with reference to the drawings.

[0009] FIG. 1 is a diagram showing an example configuration of an air conditioning system 17 according to an embodiment. The air conditioning system 17 shown in FIG. 1 is a system that conditions air in a plurality of spaces (two spaces 23 and 24 in a building 14 in FIG. 1 ). The air conditioning system 17 includes a control unit 10, a direct indoor air conditioning unit 12, and a heat source unit 40. The building 14 also includes an air conditioning unit control unit 18, two indoor air conditioning units 21, an exhaust duct 16, two variable air volume systems (VAVs) 20, and two remote controls 22. One indoor air conditioning unit 21, one VAV 20, and one remote control 22 are provided for each of the spaces 23 and 24.

[0010] The direct indoor air outdoor unit 12 adjusts the temperature of the inside air in the spaces 23 and 24. The remote control 22 is used to set the start and stop of operation, the air volume, the temperature, etc. The settings are output to the control unit 10. The control unit 10 controls the operating state of the outdoor air conditioning unit 31 and the direct indoor air outdoor unit 12 according to the settings made on the remote control 22, the temperature and humidity of the outside air and the inside air, etc.

[0011] The exhaust duct 16 is connected to exhaust ports (not shown) provided in the spaces 23 and 24. The exhaust duct 16 is a duct for discharging the air in the spaces 23 and 24 to the outside via the building 15.

[0012] The building 15 is equipped with a ventilation fan 26, an outdoor air-conditioning unit control unit 27, an outdoor air-conditioning unit 31, and an air intake 34. The ventilation fan 26 exhausts air from the exhaust duct 16. The outdoor air-conditioning unit control unit 27 controls the outdoor air-conditioning unit 31. The air intake 34 takes in outside air into the outdoor air-conditioning unit 31.

[0013] The outdoor air-conditioning unit 31 includes an outdoor air-conditioning unit blower 29, a humidifier 30, and a water coil 32. The outdoor air-conditioning unit 31 takes in outside air from an air intake 34 via an air intake duct 28. The outdoor air-conditioning unit 31 conditions (cools, heats, dehumidifies, or humidifies) the taken-in outside air. The outdoor air-conditioning unit 31 supplies the conditioned outside air from the VAV 20 via an air supply duct 25 to the spaces 23 and 24. The outdoor air-conditioning unit 31 exhausts the air from the spaces 23 and 24 to the outside of the building 13 via an exhaust duct 16 using a ventilation fan 26.

[0014] The water coil 32 is connected to the heat source unit 40. The water coil 32 is a heat exchanger that functions as a cooler for outdoor air. The water coil 32 has heat transfer tubes and heat transfer fins. In the water coil 32, heat exchange occurs between the outdoor air passing around the heat transfer tubes and heat transfer fins and the heat medium passing through the heat transfer tubes. The humidifier 30 humidifies the outdoor air that has passed through the water coil 32. The outdoor air-conditioning unit blower 29 is a blower that takes in outdoor air into the outdoor air-conditioning unit 31 and sends it to the intake air duct 25.

[0015] Various sensors are provided in the outdoor air-conditioning unit 31. Examples of sensors provided in the outdoor air-conditioning unit 31 include an outdoor air temperature sensor and an outdoor air humidity sensor that detect the temperature and humidity of the outdoor air drawn into the outdoor air-conditioning unit 31. Another example of a sensor provided in the outdoor air-conditioning unit 31 is a sensor that detects the temperature of the supply air sent to the supply air duct 25.

[0016] The air supply duct 25 obtains outside air by air blown by an outdoor air-conditioning unit blower 29. The air supply duct 25 is connected to the outdoor air-conditioning unit 31 and the VAV 20. The outdoor air-conditioning unit control unit 27 is composed of a calculation unit, a storage device, various electrical components, etc. The outdoor air-conditioning unit control unit 27 is electrically connected to the control unit 10 and the remote control 22 via communication lines. The outdoor air-conditioning unit control unit 27 controls the operating capacity of the outdoor air-conditioning unit 31 according to settings made by the remote control and the temperature of the intake outside air.

[0017] The direct in-flight outdoor unit 12 generally includes multiple outdoor units and multiple (two in FIG. 1 ) indoor conditioning units 21. The outdoor units are connected to the indoor conditioning units 21 via refrigerant connection pipes 19. Various sensors are provided in the outdoor units and the indoor conditioning units 21. Examples of sensors provided in the outdoor units include a suction pressure sensor that detects the pressure of refrigerant sucked into the compressor and a discharge pressure sensor that detects the pressure of refrigerant discharged from the compressor. Examples of sensors provided in the indoor conditioning units 21 include sensors that detect the temperature, humidity, and carbon dioxide concentration of the indoor air sucked into the indoor conditioning units 21.

[0018] The air conditioner control unit 18 is an example of an indoor control unit control unit. The air conditioner control unit 18 is composed of a calculation device, a storage device, various electrical components, etc. The air conditioner control unit 18 is connected to the direct in-house outdoor unit 12, the indoor control unit 21, sensors of the indoor control unit 21, and a remote control 22 via communication lines. The air conditioner control unit 18 controls the operating capacity of the direct in-house outdoor unit 12 and the indoor control unit 21 according to settings made by the remote control and the indoor temperature.

[0019] The control unit 10 controls the entire air conditioning system 17. The control unit 10 is composed of a calculation device and a storage device.

[0020] The communication lines L1, L2, and L3 are communication lines for communication between the air conditioner control unit 18 and the outdoor-conditioning control unit 27. The air conditioner control unit 18 communicates via the direct indoor-combustion outdoor unit 12. The outdoor-conditioning control unit 27 communicates via the heat source unit 40. There are two communication modes for the air conditioner control unit 18 and the outdoor-conditioning control unit 27: a first communication mode using the communication line L1, and a second communication mode using the communication lines L2 and L3. The first communication mode is a mode in which communication is performed directly without going through the control unit 10. When communication is performed using the first communication mode, the communication lines L2 and L3 are not required. The second communication mode is a mode in which the direct indoor-combustion outdoor unit 12 and the control unit 10 are connected via the communication line L2, and the heat source unit 40 and the control unit 10 are connected via the communication line L3. In this way, the second communication mode is a mode in which communication is performed via the control unit 10. When communication is performed using the second communication mode, the communication line L1 is not required. The communication method may be any method that allows communication between the air conditioner control unit 18 and the outdoor air conditioner control unit 27, and may be a general-purpose protocol such as Modbus.

[0021] Based on the above configuration, a first embodiment and a second embodiment will be described. [First embodiment] In the first embodiment, the air conditioner control unit 18 and the outdoor air conditioner control unit 27 are capable of communicating with each other in a first communication configuration. The air conditioner control unit 18 is configured to be able to acquire the operating capacity of the outdoor air conditioner 31 through communication. The outdoor air conditioner control unit 27 is configured to be able to acquire the operating capacity of the indoor air conditioner 21 through communication.

[0022] The air conditioner control unit 18 is preset with a first threshold T1 for comparison with the operating capacity of the outdoor air-conditioning unit 31 and a second threshold T2 that is smaller than the first threshold T1. The first threshold T1 and the second threshold T2 are stored in a storage device of the air conditioner control unit 18. The first threshold T1 and the second threshold T2 are set, for example, via the control unit 10. The air conditioner control unit 18 increases the operating capacity of the indoor air-conditioning unit 21 when the operating capacity of the outdoor air-conditioning unit 31 is equal to or greater than the first threshold T1 and the operating capacity of the indoor air-conditioning unit 21 can be increased. Furthermore, the air conditioner control unit 18 reduces the operating capacity of the indoor air-conditioning unit 21 when the operating capacity of the outdoor air-conditioning unit 31 is less than the second threshold T2 and the operating capacity of the indoor air-conditioning unit 21 can be reduced. Control to reduce the operating capacity of the indoor air-conditioning unit 21 also includes control to stop operation of the indoor air-conditioning unit 21.

[0023] The outdoor-conditioning unit control unit 27 is preset with a third threshold T3 for comparison with the operating capacity of the indoor-conditioning unit 21, and a fourth threshold T4 that is smaller than the third threshold T3. The third threshold T3 and the fourth threshold T4 are stored in a storage device of the outdoor-conditioning unit control unit 27. The third threshold T3 and the fourth threshold T4 are set, for example, via the control unit 10. The outdoor-conditioning unit control unit 27 increases the operating capacity of the outdoor-conditioning unit 31 when the operating capacity of the indoor-conditioning unit 21 is equal to or greater than the third threshold T3 and the operating capacity of the outdoor-conditioning unit 31 can be increased. Furthermore, the outdoor-conditioning unit control unit 27 reduces the operating capacity of the outdoor-conditioning unit 31 when the operating capacity of the indoor-conditioning unit 21 is less than the fourth threshold T4 and the operating capacity of the outdoor-conditioning unit 31 can be reduced. Control to reduce the operating capacity of the outdoor-conditioning unit 31 also includes control to stop operation of the outdoor-conditioning unit 31.

[0024] 2 is a flowchart showing the processing flow of the air conditioning system 17 in the first embodiment. The air conditioner control unit 18 determines whether the operating capacity of the outdoor air-conditioning unit 31 is equal to or greater than a threshold value T1 (step S101). If the operating capacity of the outdoor air-conditioning unit 31 is equal to or greater than the threshold value T1 (step S101: YES) and the operating capacity of the indoor air-conditioning unit 21 can be increased, the air conditioner control unit 18 increases the operating capacity of the indoor air-conditioning unit 21 (step S102) and proceeds to step S105.

[0025] If the operating capacity of the outdoor air-conditioning unit 31 is not equal to or greater than threshold T1 (step S101: NO), the air conditioner control unit 18 determines whether the operating capacity of the outdoor air-conditioning unit 31 is less than threshold T2 (step S102). If the operating capacity of the outdoor air-conditioning unit 31 is less than threshold T2 (step S103: YES) and the operating capacity of the indoor air-conditioning unit 21 can be reduced, the air conditioner control unit 18 reduces the operating capacity of the indoor air-conditioning unit 21 (step S104) and proceeds to step S105. If the operating capacity of the outdoor air-conditioning unit 31 is not less than threshold T2 (step S103: NO), proceeds to step S105.

[0026] The outdoor-conditioning unit control unit 27 determines whether the operating capacity of the indoor-conditioning unit 21 is equal to or greater than the threshold value T3 (step S105). If the operating capacity of the indoor-conditioning unit 21 is equal to or greater than the threshold value T3 (step S105: YES), and the operating capacity of the outdoor-conditioning unit 31 can be increased, the outdoor-conditioning unit control unit 27 increases the operating capacity of the outdoor-conditioning unit 31 (step S106), and ends the process.

[0027] If the operating capacity of the indoor processing unit 21 is not equal to or greater than threshold T3 (step S105: NO), the outdoor processing unit control unit 27 determines whether the operating capacity of the indoor processing unit 21 is less than threshold T4 (step S107). If the operating capacity of the indoor processing unit 21 is less than threshold T4 (step S107: YES) and the operating capacity of the outdoor processing unit 31 can be reduced, the outdoor processing unit control unit 27 reduces the operating capacity of the outdoor processing unit 31 (step S108) and terminates the processing. If the operating capacity of the indoor processing unit 21 is not less than threshold T4 (step S107: NO), the processing terminates.

[0028] 2 may be a loop process that returns to step S101 after step S106 or step S108 is completed, rather than ending at step S106 or step S108. Alternatively, this process may be repeated periodically (for example, every minute). This process may be performed in response to an instruction from an operator of the air conditioning system 17.

[0029] The above is the basic processing flow in the first embodiment. As shown in the flowchart of Fig. 2, the purpose of the processing in this embodiment is to prevent the load from being biased to either the outdoor air-conditioning unit 31 or the indoor air-conditioning unit 21. If it is possible to prevent the load from being biased to either the outdoor air-conditioning unit 31 or the indoor air-conditioning unit 21, processing may be added to or changed in the processing shown in the flowchart of Fig. 2.

[0030] Specifically, a processing example will be described in which thresholds T1 and T3 are set to 80% operating capacity and thresholds T2 and T4 are set to 70% operating capacity. First, when the operating capacity of the indoor unit 21 reaches 80% or more and the set dehumidification performance is achieved, the air conditioner control unit 18 increases the airflow of the indoor unit 21, and the outdoor unit control unit 27 increases the operating capacity of the outdoor unit. When the operating capacity of the indoor unit 21 is less than threshold T1 but greater than or equal to threshold T3, the outdoor unit control unit 27 does not perform airflow correction control but instead controls the indoor unit 21 to equalize its operating capacity. When the operating capacity of the outdoor unit 31 falls below 70%, the air conditioner control unit 18 gradually reduces the airflow correction and transitions to normal control. Here, normal control refers to control of the direct-in-the-room outdoor unit 12 and the indoor unit 21, which is performed according to settings via the remote control or the indoor temperature.

[0031] For example, if the operating capacity of the indoor air-conditioning unit 21 is 80% or more and the operating capacity of the outdoor air-conditioning unit 31 is 100%, the operating capacity of the outdoor air-conditioning unit 31 cannot be increased. However, if the ventilation air volume is sufficient, the outdoor air-conditioning unit control unit 27 reduces the load on the outdoor air-conditioning unit 31 (by reducing the air volume, changing the set temperature of the heat source unit, or reducing the water flow rate). This increases the load on the indoor air-conditioning unit 21, but reduces the load on the outdoor air-conditioning unit 31, making it possible to prevent the load from being biased toward either the outdoor air-conditioning unit 31 or the indoor air-conditioning unit 21.

[0032] By controlling in this way, it is possible to prevent the load from being biased towards either the outdoor air-conditioning unit 31 or the indoor air-conditioning unit 21. This makes it possible to prevent parts of equipment operating at high loads from breaking down easily and to prevent the maintenance cycle of equipment operating at high loads from being shortened, thereby reducing the running costs of the air-conditioning system.

[0033] [Second embodiment] In the second embodiment, the air conditioner control unit 18 and the outdoor air conditioner control unit 27 can communicate with each other using the first communication format or the second communication format. The air conditioner control unit 18 is configured to be able to acquire the operating capacity of the outdoor air conditioner 31 through communication. The outdoor air conditioner control unit 27 is configured to be able to acquire the operating capacity of the indoor air conditioner 21 through communication.

[0034] A predetermined value A (>0) for comparing the difference between the operating capacity of the outdoor air-conditioning unit 31 and the operating capacity of the indoor air-conditioning unit 21 is preset in the air-conditioning unit control unit 18. The predetermined value A is stored in the storage device of the air-conditioning unit control unit 18. Similarly, the predetermined value A is preset in the outdoor air-conditioning unit control unit 27. The predetermined value A is stored in the storage device of the outdoor air-conditioning unit control unit 27. The predetermined value A is set, for example, via the control unit 10.

[0035] The air conditioner control unit 18 increases the operating capacity of the indoor processing unit 21 when the difference between the operating capacity X of the outdoor processing unit 31 and the operating capacity Y of the indoor processing unit 21 is equal to or greater than a predetermined value A (X-Y≧A) and it is possible to increase the operating capacity of the indoor processing unit 21. Furthermore, the air conditioner control unit 18 decreases the operating capacity of the indoor processing unit 21 when the difference between the operating capacity of the outdoor processing unit 31 and the operating capacity of the indoor processing unit 21 is less than a predetermined value (X-Y<A) and it is possible to decrease the operating capacity of the indoor processing unit 21. Control to decrease the operating capacity of the indoor processing unit 21 also includes control to stop the operation of the indoor processing unit 21.

[0036] The outdoor processing unit control unit 27 increases the operating capacity of the outdoor processing unit 31 when the difference between the operating capacity Y of the indoor processing unit 21 and the operating capacity X of the outdoor processing unit 31 is equal to or greater than a predetermined value A (Y-X≧A) and it is possible to increase the operating capacity of the outdoor processing unit 31. Furthermore, the outdoor processing unit control unit 27 decreases the operating capacity of the outdoor processing unit 31 when the difference between the operating capacity of the indoor processing unit 21 and the operating capacity of the outdoor processing unit 31 is less than a predetermined value (Y-X<A) and it is possible to decrease the operating capacity of the outdoor processing unit 31. Control to decrease the operating capacity of the outdoor processing unit 31 also includes control to stop the operation of the outdoor processing unit 31.

[0037] Figure 3 is a flowchart showing the processing flow of the air conditioning system 17 in the second embodiment. In the flowchart of Figure 3, the difference (X-Y) between the operating capacity X of the outdoor air-conditioning unit 31 and the operating capacity Y of the indoor air-conditioning unit 21 is defined as Z. The difference (Y-X) between the operating capacity Y of the indoor air-conditioning unit 21 and the operating capacity X of the outdoor air-conditioning unit 31 is defined as W.

[0038] The air conditioner control unit 18 determines whether the difference Z between the operating capacity X of the outdoor processing unit 31 and the operating capacity Y of the indoor processing unit 21 is equal to or greater than a predetermined value A (step S201). If the difference Z between the operating capacity X of the outdoor processing unit 31 and the operating capacity Y of the indoor processing unit 21 is equal to or greater than the predetermined value A (step S201: YES) and the operating capacity of the indoor processing unit 21 can be increased, the air conditioner control unit 18 increases the operating capacity of the indoor processing unit 21 (step S202) and proceeds to step S205.

[0039] If the difference Z between the operating capacity X of the outdoor air-conditioning unit 31 and the operating capacity Y of the indoor air-conditioning unit 21 is not equal to or greater than the predetermined value A (step S201: NO), the air conditioner control unit 18 determines whether the difference Z between the operating capacity X of the outdoor air-conditioning unit 31 and the operating capacity Y of the indoor air-conditioning unit 21 has changed from a state equal to or greater than the predetermined value A to a state less than the predetermined value A (step S203). If the difference Z between the operating capacity X of the outdoor air-conditioning unit 31 and the operating capacity Y of the indoor air-conditioning unit 21 has changed from a state equal to or greater than the predetermined value A to a state less than the predetermined value A (step S203: YES), and if the operating capacity of the indoor air-conditioning unit 21 can be reduced, the air conditioner control unit 18 reduces the operating capacity of the indoor air-conditioning unit 21 (step S204) and proceeds to step S205. If the difference Z between the operating capacity X of the outdoor air-conditioning unit 31 and the operating capacity Y of the indoor air-conditioning unit 21 has not changed from a state equal to or greater than the predetermined value A to a state less than the predetermined value A (step S203: NO), the air conditioner control unit 18 proceeds to step S205.

[0040] The outdoor-conditioning unit control unit 27 determines whether the difference W between the operating capacity Y of the indoor processing unit 21 and the operating capacity X of the outdoor processing unit 31 is equal to or greater than a predetermined value A (step S205). If the difference W between the operating capacity Y of the indoor processing unit 21 and the operating capacity X of the outdoor processing unit 31 is equal to or greater than the predetermined value A (step S205: YES) and the operating capacity of the outdoor processing unit 31 can be increased, the outdoor-conditioning unit control unit 27 increases the operating capacity of the outdoor processing unit 31 (step S206) and ends the process.

[0041] If the difference W between the operating capacity Y of the indoor processing unit 21 and the operating capacity X of the outdoor processing unit 31 is not equal to or greater than the predetermined value A (step S205: NO), the outdoor processing unit control unit 27 determines whether the difference W between the operating capacity Y of the indoor processing unit 21 and the operating capacity X of the outdoor processing unit 31 has changed from a state equal to or greater than the predetermined value A to a state less than the predetermined value A (step S207). If the difference W between the operating capacity Y of the indoor processing unit 21 and the operating capacity X of the outdoor processing unit 31 has changed from a state equal to or greater than the predetermined value A to a state less than the predetermined value A (step S207: YES), and if the operating capacity of the outdoor processing unit 31 can be reduced, the outdoor processing unit control unit 27 reduces the operating capacity of the outdoor processing unit 31 (step S208) and terminates the process. If the difference W between the operating capacity Y of the indoor processing unit 21 and the operating capacity X of the outdoor processing unit 31 has not changed from a state equal to or greater than the predetermined value A to a state less than the predetermined value A (step S207: NO), the process terminates.

[0042] The process shown in FIG. 3 may be performed periodically (for example, every minute) or in response to an instruction from an operator of the air conditioning system 17 .

[0043] The above is the basic processing flow in the second embodiment. As shown in the flowchart of Fig. 3, the purpose of the processing in this embodiment is to prevent the load from being biased to either the outdoor air-conditioning unit 31 or the indoor air-conditioning unit 21. If it is possible to prevent the load from being biased to either the outdoor air-conditioning unit 31 or the indoor air-conditioning unit 21, processing may be added to or changed in the processing shown in the flowchart of Fig. 3.

[0044] Specifically, a processing example in which the predetermined value A is set to 20% will be described. When the difference W between the operating capacity Y of the indoor air-conditioning unit 21 and the operating capacity X of the outdoor air-conditioning unit 31 is 20% or more, the operating capacity is set to a value at which the outdoor air-conditioning unit 31 can achieve its desired dehumidifying performance. In this case, the outdoor air-conditioning unit control unit 27 increases the operating capacity of the outdoor air-conditioning unit 31 by increasing the airflow rate or lowering the discharge temperature. This equalizes the load, thereby preventing the load from being imbalanced on either the outdoor air-conditioning unit 31 or the indoor air-conditioning unit 21. When the difference W between the operating capacity Y of the indoor air-conditioning unit 21 and the operating capacity X of the outdoor air-conditioning unit 31 falls from 20% or more to less than 20%, the air-conditioning unit control unit 18 stops the operation of the indoor air-conditioning unit 21, and the outdoor air-conditioning unit control unit 27 performs normal control of only the outdoor air-conditioning unit 31. Here, normal control refers to control by the outdoor air-conditioning unit control unit 27, which is performed based on settings via the remote control or the intake outdoor air temperature. In this way, by stopping the equipment with the high load out of the outdoor air-conditioning unit 31 and the indoor air-conditioning unit 21, the operating time of the equipment with the high load is reduced.

[0045] This makes it possible to prevent the load from being biased toward either the outdoor air-conditioning unit 31 or the indoor air-conditioning unit 21. This makes it possible to prevent parts of equipment operating under high load from breaking down more easily and to prevent the maintenance cycle of equipment operating under high load from being shortened, thereby reducing the running costs of the air-conditioning system.

[0046] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0047] 10...control unit, 12...direct indoor outdoor unit, 14, 15...building, 16...exhaust duct, 17...air conditioning system, 18...air conditioner control unit, 19...refrigerant connection pipe, 21...indoor air conditioning unit, 22...remote control, 23, 24...space, 25...air supply duct, 26...ventilation fan, 27...outdoor air conditioning unit control unit, 28...intake duct, 29...outdoor air conditioning unit blower, 30...humidifier, 31...outdoor air conditioning unit, 32...water coil, 34...air intake port, 40...heat source unit, L1, L2, L3...communication line

Claims

1. An air conditioning system including an indoor air conditioning unit and an outdoor air conditioning unit, an indoor-conditioning unit control unit that increases the operating capacity of the indoor-conditioning unit when the operating capacity of the outdoor-conditioning unit is equal to or greater than a first threshold value and the operating capacity of the indoor-conditioning unit can be increased, and that decreases the operating capacity of the indoor-conditioning unit when the operating capacity of the outdoor-conditioning unit is less than a second threshold value that is smaller than the first threshold value and the operating capacity of the indoor-conditioning unit can be decreased; an outdoor air-conditioning unit control unit that increases the operating capacity of the outdoor air-conditioning unit when the operating capacity of the indoor air-conditioning unit is equal to or greater than a third threshold and the operating capacity of the outdoor air-conditioning unit can be increased, and that decreases the operating capacity of the outdoor air-conditioning unit when the operating capacity of the indoor air-conditioning unit is less than a fourth threshold that is smaller than the third threshold and the operating capacity of the outdoor air-conditioning unit can be decreased; Equipped with an air conditioning system.

2. An air conditioning system including an indoor air conditioning unit and an outdoor air conditioning unit, an indoor-conditioning unit control unit that increases the operating capacity of the indoor-conditioning unit when the difference between the operating capacity of the outdoor-conditioning unit and the operating capacity of the indoor-conditioning unit becomes equal to or greater than a predetermined value and the operating capacity of the indoor-conditioning unit can be increased, and that decreases the operating capacity of the indoor-conditioning unit when the difference between the operating capacity of the outdoor-conditioning unit and the operating capacity of the indoor-conditioning unit becomes less than the predetermined value and the operating capacity of the indoor-conditioning unit can be decreased; an outdoor air-conditioning unit control unit that increases the operating capacity of the outdoor air-conditioning unit when the difference between the operating capacity of the indoor air-conditioning unit and the operating capacity of the outdoor air-conditioning unit becomes equal to or greater than a predetermined value and the operating capacity of the outdoor air-conditioning unit can be increased, and that decreases the operating capacity of the outdoor air-conditioning unit when the difference between the operating capacity of the indoor air-conditioning unit and the operating capacity of the outdoor air-conditioning unit becomes less than the predetermined value and the operating capacity of the outdoor air-conditioning unit can be decreased; Equipped with an air conditioning system.

3. A control method for an air conditioning system including an indoor air conditioning unit and an outdoor air conditioning unit, When the operating capacity of the outdoor air-conditioning unit is equal to or greater than a first threshold value and the operating capacity of the indoor air-conditioning unit can be increased, the operating capacity of the indoor air-conditioning unit is increased, and when the operating capacity of the outdoor air-conditioning unit is less than a second threshold value that is smaller than the first threshold value and the operating capacity of the indoor air-conditioning unit can be reduced, the operating capacity of the indoor air-conditioning unit is reduced; A control method in which, when the operating capacity of the indoor air conditioning unit is equal to or greater than a third threshold and the operating capacity of the outdoor air conditioning unit can be increased, the operating capacity of the outdoor air conditioning unit is increased, and, when the operating capacity of the indoor air conditioning unit is less than a fourth threshold that is smaller than the third threshold and the operating capacity of the outdoor air conditioning unit can be reduced, the operating capacity of the outdoor air conditioning unit is reduced.

4. A control method for an air conditioning system including an indoor air conditioning unit and an outdoor air conditioning unit, When the difference between the operating capacity of the outdoor air-conditioning unit and the operating capacity of the indoor air-conditioning unit becomes equal to or greater than a predetermined value and the operating capacity of the indoor air-conditioning unit can be increased, the operating capacity of the indoor air-conditioning unit is increased, and when the difference between the operating capacity of the outdoor air-conditioning unit and the operating capacity of the indoor air-conditioning unit becomes less than the predetermined value and the operating capacity of the indoor air-conditioning unit can be reduced, the operating capacity of the indoor air-conditioning unit is reduced; A control method in which, when the difference between the operating capacity of the indoor air conditioning unit and the operating capacity of the outdoor air conditioning unit becomes equal to or greater than a predetermined value and the operating capacity of the outdoor air conditioning unit can be increased, the operating capacity of the outdoor air conditioning unit is increased, and, when the difference between the operating capacity of the indoor air conditioning unit and the operating capacity of the outdoor air conditioning unit becomes less than the predetermined value and the operating capacity of the outdoor air conditioning unit can be reduced, the operating capacity of the outdoor air conditioning unit is reduced.