Air conditioning control apparatus and air conditioning system

[0001] This application is a Continuation of PCT International Application No. PCT/JP2022/015647, filed on Mar. 29, 2022, which claims priority under 35 U.S.C. § 119(a) to Patent Application No. JP 2021-061277, filed in Japan on Mar. 31, 2021, all of which are hereby expressly incorporated by reference into the present application.

[0002] The present invention relates to an air conditioning control apparatus and an air conditioning system.

[0003] As disclosed in Patent Literature 1 (JP H05-312378 A), there is a technique for controlling a circulation amount of a refrigerant to be equal between indoor units when there is an extreme difference in a distribution ratio of the refrigerant between the indoor units in order to improve a non-uniform temperature distribution in a space.

[0004] An air conditioning control apparatus according to a first aspect controls a plurality of indoor units. The air conditioning control apparatus sets the indoor units having been designated among the plurality of indoor units as an indoor unit group. The air conditioning control apparatus causes a first indoor unit belonging to the indoor unit group to perform a cooling operation or a heating operation and causes a second indoor unit belonging to the indoor unit group to perform a fan operation or a ventilation operation when a difference of a certain level or more occurs in thermal loads to be processed by each of the indoor units belonging to the indoor unit group.

(1) Overall Configuration

[0012] An air conditioning system 1 constitutes a vapor compression refrigeration cycle and performs air conditioning of a target space SP (space). In the present embodiment, the air conditioning system 1 is a so-called multi-air conditioning system for buildings. FIG. 1 is a schematic configuration diagram of the air conditioning system 1. As shown in FIG. 1, the air conditioning system 1 mainly includes an air conditioning control apparatus 10 and a plurality of indoor units 20a to 20d. The air conditioning system 1 includes outdoor units 30a and 30b and a ventilator 40. The indoor units 20a to 20d, the outdoor units 30a and 30b, and the ventilator 40 are installed in the target space SP.

[0013] The outdoor units 30a and 30b and the air conditioning control apparatus 10 are communicably connected by a communication line 80. The outdoor unit 30a is communicably connected to the indoor units 20a and 20b and the ventilator 40 via the communication line 80. The outdoor unit 30b is communicably connected to the indoor units 20c and 20d via the communication line 80.

[0014] The outdoor unit 30a and the indoor units 20a and 20b constitute a refrigerant system RS1. The outdoor unit 30b and the indoor units 20c and 20d constitute a refrigerant system RS2. FIG. 2 is a diagram showing the refrigerant system RS1 of a refrigerant circuit 50. As shown in FIG. 2, the outdoor unit 30a and the indoor units 20a and 20b are connected via a liquid refrigerant connection pipe 51 and a gas refrigerant connection pipe 52 to constitute the refrigerant circuit 50.

[0015] In the present embodiment, the indoor units 20a to 20d perform a cooling operation, a heating operation, a fan operation, or a ventilation operation. The cooling operation is an operation of cooling air in the target space SP. The heating operation is an operation of heating air in the target space SP. The fan operation is an operation of stirring or circulating the air in the target space SP. The ventilation operation is an operation of taking out indoor air RA from the target space SP and taking outdoor air OA into the target space SP by using the ventilator 40. In the present embodiment, the indoor unit 20a is connected to the ventilator 40 by an air supply duct 72. The indoor unit 20a can perform the ventilation operation in conjunction with the ventilator 40.

(2) Detailed Configuration

[0016] Hereinafter, the air conditioning control apparatus 10, the indoor units 20a and 20b, the outdoor unit 30a, and the ventilator 40 included in the air conditioning system 1 will be described in detail. The description of the indoor units 20c and 20d and the outdoor unit 30b is basically similar to the description of the indoor units 20a and 20b and the outdoor unit 30a except for the presence or absence of the ventilator 40, and thus, will be omitted unless otherwise necessary.

(2-1) Indoor Units

[0017] The indoor units 20a and 20b are installed in the target space SP in a building or the like. In the present embodiment, the indoor units 20a and 20b are ceiling embedded units to be installed in a ceiling. As shown in FIG. 2, the indoor units 20a and 20b mainly include indoor heat exchangers 21a and 21b, indoor fans 22a and 22b, indoor expansion valves 23a and 23b, indoor control units 29a and 29b, liquid-side temperature sensors 61a and 61b, gas-side temperature sensors 62a and 62b, indoor temperature sensors 63a and 63b, and human detection sensors 64a and 64b. As shown in FIG. 2, the indoor units 20a and 20b include liquid refrigerant pipes 53a and 53b that connect liquid-side ends of the indoor heat exchangers 21a and 21b and the liquid refrigerant connection pipe 51, and gas refrigerant pipes 53c and 53d that connect gas-side ends of the indoor heat exchangers 21a and 21b and the gas refrigerant connection pipe 52.

(2-1-1) Indoor Heat Exchangers

[0018] The indoor heat exchangers 21a and 21b are not limited in structure. For example, the indoor heat exchangers 21a and 21b are cross-fin type fin-and-tube heat exchangers that includes a heat transfer tube (not shown) and a large number of fines (not shown). The indoor heat exchangers 21a and 21b exchange heat between the refrigerant flowing through the indoor heat exchangers 21a and 21b and the indoor air RA in the target space SP.

[0019] The indoor heat exchangers 21a and 21b function as an evaporator during the cooling operation. The indoor heat exchangers 21a and 21b function as a condenser during the heating operation.

(2-1-2) Indoor Fans

[0020] The indoor fans 22a and 22b suck the indoor air RA into the indoor units 20a and 20b, supply the indoor air RA to the indoor heat exchangers 21a and 21b, and supply the indoor air RA subjected to heat exchange with the refrigerant in the indoor heat exchangers 21a and 21b to the target space SP. The indoor fans 22a and 22b are, for example, centrifugal fans such as turbo fans or sirocco fans. The indoor fans 22a and 22b are driven by indoor fan motors 22am and 22bm. The indoor fan motors 22am and 22bm have the number of rotations controllable by an inverter.

(2-1-3) Indoor Expansion Valves

[0021] The indoor expansion valves 23a and 23b are mechanisms for adjusting pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipes 53a and 53b. The indoor expansion valves 23a and 23b are provided in the liquid refrigerant pipes 53a and 53b. In the present embodiment, the indoor expansion valves 23a and 23b are electronic expansion valves whose opening degrees are adjustable.

(2-1-4) Sensors

[0022] The liquid-side temperature sensors 61a and 61b measure a temperature of the refrigerant flowing through the liquid refrigerant pipes 53a and 53b. The liquid-side temperature sensors 61a and 61b are provided in the liquid refrigerant pipes 53a and 53b.

[0023] The gas-side temperature sensors 62a and 62b measure a temperature of the refrigerant flowing through the gas refrigerant pipes 53c and 53d. The gas-side temperature sensors 62a and 62b are provided in the gas refrigerant pipes 53c and 53d.

[0024] The indoor temperature sensors 63a and 63b measure a temperature of the indoor air RA in the target space SP. The indoor temperature sensors 63a and 63b are provided near suction ports of the indoor air RA of the indoor units 20a and 20b.

[0025] The liquid-side temperature sensors 61a and 61b, the gas-side temperature sensors 62a and 62b, and the indoor temperature sensors 63a and 63b are, for example, thermistors.

[0026] The human detection sensors 64a and 64b detect a person in the target space SP. The human detection sensors 64a and 64b are provided in front of the indoor units 20a and 20b. The human detection sensors 64a and 64b are, for example, human detection cameras or infrared sensors.

(2-1-5) Indoor Control Units

[0027] The indoor control units 29a and 29b control the operation of each component constituting the indoor units 20a and 20b.

[0028] The indoor control units 29a and 29b are electrically connected to various devices of the indoor units 20a and 20b, which include the indoor expansion valves 23a and 23b and the indoor fan motors 22am and 22bm. The indoor control units 29a and 29b are communicably connected to various sensors provided in the indoor units 20a and 20b, which include the liquid-side temperature sensors 61a and 61b, the gas-side temperature sensors 62a and 62b, the indoor temperature sensors 63a and 63b, and the human detection sensors 64a and 64b.

[0029] The indoor control units 29a and 29b include a control calculator and a storage device. The control calculator is a processor such as a CPU or a GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control calculator reads a program from the storage device and executes predetermined calculation processing in accordance with the program to control the operation of each component constituting the indoor units 20a and 20b. In addition, the control calculator is capable of writing a result of calculation to the storage device and reading information from the storage device in accordance with the program. The indoor control units 29a and 29b also include a timer.

[0030] The indoor control units 29a and 29b are configured to receive various signals from an operation remote controller (not shown). The various signals include, for example, signals instructing a start and a stop of an operation, and signals related to various settings. The signals related to various settings include, for example, a signal for a set temperature and a signal for a set humidity. The indoor control units 29a and 29b exchange control signals, measurement signals, signals related to various settings, and the like with the outdoor control unit 39a of the outdoor unit 30a, the ventilation control unit 49 of the ventilator 40, and the control unit 13 of the air conditioning control apparatus 10 via the communication line 80.

[0031] The indoor control units 29a and 29b, the outdoor control unit 39a, and the ventilation control unit 49 cooperate to function as a controller CL. The function of the controller C1 will be described later.

(2-2) Outdoor Unit

[0032] The outdoor unit 30a is a unit installed on a rooftop or the like of a building in which the refrigerant system RS1 is installed. As shown in FIG. 2, the outdoor unit 30a mainly includes a compressor 31a, a flow direction switching mechanism 32a, an outdoor heat exchanger 33a, an outdoor expansion valve 34a, an accumulator 35a, an outdoor fan 36a, a liquid-side shutoff valve 37a, a gas-side shutoff valve 38a, an outdoor control unit 39a, a suction pressure sensor 65a, a discharge pressure sensor 66a, a heat exchange temperature sensor 67a, and an outdoor temperature sensor 68a. The outdoor unit 30a also includes a suction pipe 54a, a discharge pipe 54b, a first gas refrigerant pipe 54c, a liquid refrigerant pipe 54d, and a second gas refrigerant pipe 54e.

[0033] The suction pipe 54a connects the flow direction switching mechanism 32a and a suction side of the compressor 31a. The suction pipe 54a is provided with the accumulator 35a. The discharge pipe 54b connects a discharge side of the compressor 31a and the flow direction switching mechanism 32a. The first gas refrigerant pipe 54c connects the flow direction switching mechanism 32a and a gas-side end of the outdoor heat exchanger 33a. The liquid refrigerant pipe 54d connects a liquid side of the outdoor heat exchanger 33a and the liquid refrigerant connection pipe 51. The liquid refrigerant pipe 54d is provided with the outdoor expansion valve 34a. The liquid-side shutoff valve 37a is provided at a connection portion between the liquid refrigerant pipe 54d and the liquid refrigerant connection pipe 51. The second gas refrigerant pipe 54e connects the flow direction switching mechanism 32a and the gas refrigerant connection pipe 52. The gas-side shutoff valve 38a is provided at a connection portion between the second gas refrigerant pipe 54e and the gas refrigerant connection pipe 52.

(2-2-1) Compressor

[0034] As shown in FIG. 2, the compressor 31a is a device that sucks a low-pressure refrigerant in a refrigeration cycle from the suction pipe 54a, compresses the refrigerant by a compression mechanism (not shown), and discharges the compressed refrigerant to the discharge pipe 54b.

[0035] The type of the compressor 31a may be of any type. For example, the compressor 31a is a rotary type or scroll type capacity compressor. The compressor 31a includes a compression mechanism (not shown) driven by a compressor motor 31am. The compressor motor 31am has the number of rotations controllable by an inverter.

(2-2-2) Flow Direction Switching Mechanism

[0036] The flow direction switching mechanism 32a is a mechanism that changes a state of the outdoor heat exchanger 33a between a first state of functioning as an evaporator and a second state of functioning as a condenser by switching a flow direction of the refrigerant. When the flow direction switching mechanism 32a sets the state of the outdoor heat exchanger 33a to the first state, the indoor heat exchangers 21a and 21b function as a condenser. On the other hand, when the flow direction switching mechanism 32a sets the state of the outdoor heat exchanger 33a to the second state, the indoor heat exchangers 21a and 21b function as an evaporator.

[0037] As shown in FIG. 2, the flow direction switching mechanism 32a is configured to switch the flow direction of the refrigerant discharged from the compressor 31a between a first flow direction A and a second flow direction B. When the flow direction switching mechanism 32a switches the flow direction of the refrigerant to the first flow direction A, the state of the outdoor heat exchanger 33a becomes the first state. When the flow direction switching mechanism 32a switches the flow direction of the refrigerant to the second flow direction B, the state of the outdoor heat exchanger 33a becomes the second state.

[0038] In the present embodiment, the flow direction switching mechanism 32a is a four-way switching valve.

[0039] During the heating operation, the flow direction of the refrigerant discharged from the compressor 31a is switched to the first flow direction A by the flow direction switching mechanism 32a. When the flow direction of the refrigerant is set to the first flow direction A, the flow direction switching mechanism 32a causes the suction pipe 54a to communicate with the first gas refrigerant pipe 54c and causes the discharge pipe 54b to communicate with the second gas refrigerant pipe 54e as indicated by a broken line in the flow direction switching mechanism 32a in FIG. 2. When the refrigerant flows in the first flow direction A, the refrigerant discharged from the compressor 31a flows through the refrigerant circuit 50 in the order of the indoor heat exchangers 21a and 21b, the indoor expansion valves 23a and 23b, the outdoor expansion valve 34a, and the outdoor heat exchanger 33a, and returns to the compressor 31a.

[0040] During the cooling operation, the flow direction of the refrigerant discharged from the compressor 31a is switched to the second flow direction B by the flow direction switching mechanism 32a. When the flow direction of the refrigerant is set to the second flow direction B, the flow direction switching mechanism 32a causes the suction pipe 54a to communicate with the second gas refrigerant pipe 54e and causes the discharge pipe 54b to communicate with the first gas refrigerant pipe 54c as indicated by a solid line in the flow direction switching mechanism 32a in FIG. 2. When the refrigerant flows in the second flow direction B, the refrigerant discharged from the compressor 31a flows through the refrigerant circuit 50 in the order of the outdoor heat exchanger 33a, the outdoor expansion valve 34a, the indoor expansion valves 23a and 23b, and the indoor heat exchangers 21a and 21b, and returns to the compressor 31a.

(2-2-3) Outdoor Heat Exchanger

[0041] In the outdoor heat exchanger 33a, heat is exchanged between the refrigerant flowing through the outdoor heat exchanger 33a and the outdoor air OA. The outdoor heat exchanger 33a may have any structure. For example, the outdoor heat exchanger 33a is a cross-fin type fin-and-tube heat exchanger including a heat transfer tube (not shown) and a plurality of fines (not shown).

[0042] The outdoor heat exchanger 33a functions as an evaporator during the heating operation and as a condenser during the cooling operation.

(2-2-4) Outdoor Expansion Valve

[0043] The outdoor expansion valve 34a is mechanisms for adjusting pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipe 54d. As shown in FIG. 2, the outdoor expansion valve 34a is provided in the liquid refrigerant pipe 54d. In the present embodiment, the outdoor expansion valve 34a is an electronic expansion valve whose opening degree is adjustable.

(2-2-5) Accumulator

[0044] The accumulator 35a has a gas liquid separating function of separating refrigerant flowing into the accumulator 35a into a gas refrigerant and a liquid refrigerant. As shown in FIG. 2, the accumulator 35a is provided in the suction pipe 54a. The refrigerant flowing into the accumulator 35a is separated into a gas refrigerant and a liquid refrigerant, and the gas refrigerant collecting in an upper space flows into the compressor 31a.

(2-2-6) Outdoor Fan

[0045] The outdoor fan 36a is a fan that sucks outdoor air OA into the outdoor unit 30a, supplies the outdoor air OA to the outdoor heat exchanger 33a, and discharges the outdoor air OA subjected to heat exchange with the refrigerant in the outdoor heat exchanger 33a to the outside of the outdoor unit 30a.

[0046] The outdoor fan 36a is, for example, an axial fan such as a propeller fan. The outdoor fan 36a is driven by an outdoor fan motor 36am. The outdoor fan motor 36am has the number of rotations controllable by an inverter.

(2-2-7) Liquid-Side Shutoff Valve and Gas-Side Shutoff Valve

[0047] As shown in FIG. 2, the liquid-side shutoff valve 37a is a valve provided at a connection portion between the liquid refrigerant pipe 54d and the liquid refrigerant connection pipe 51. The gas-side shutoff valve 38a is a valve provided at a connection portion between the second gas refrigerant pipe 54e and the gas refrigerant connection pipe 52. The liquid-side shutoff valve 37a and the gas-side shutoff valve 38a are, for example, manually operated valves.

(2-2-8) Sensors

[0048] The suction pressure sensor 65a is a sensor that measures a suction pressure. The suction pressure sensor 65a is provided in the suction pipe 54a. The suction pressure is a low pressure value of the refrigeration cycle.

[0049] The discharge pressure sensor 66a is a sensor that measures a discharge pressure. The discharge pressure sensor 66a is provided in the discharge pipe 54b. The discharge pressure is a high pressure value of the refrigeration cycle.

[0050] The heat exchanger temperature sensor 67a measures a temperature of the refrigerant flowing in the outdoor heat exchanger 33a. The heat exchange temperature sensor 67a is provided in the outdoor heat exchanger 33a. The heat exchange temperature sensor 67a measures a refrigerant temperature corresponding to a condensation temperature during the cooling operation, and measures a refrigerant temperature corresponding to an evaporation temperature during the heating operation.

[0051] The outdoor temperature sensor 68a measures a temperature of the outdoor air OA in the target space SP. The outdoor temperature sensor 68a is provided near a suction port of the outdoor air OA of the outdoor unit 30a.

(2-2-9) Outdoor Control Unit

[0052] The outdoor control unit 39a controls the operation of each component constituting the outdoor unit 30a.

[0053] The outdoor control unit 39a is electrically connected to various devices of the outdoor unit 30a, which include the compressor motor 31am, the flow direction switching mechanism 32a, the outdoor expansion valve 34a, and the outdoor fan motor 36am. The outdoor control unit 39a is communicably connected to various sensors provided in the outdoor unit 30a, which include the suction pressure sensor 65a, the discharge pressure sensor 66a, the heat exchange temperature sensor 67a, and the outdoor temperature sensor 68a.

[0054] The outdoor control unit 39a includes a control calculator and a storage device. The control calculator is a processor such as a CPU or a GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control calculator reads a program from the storage device and executes predetermined calculation processing in accordance with the program to control the operation of each component constituting the outdoor unit 30a. In addition, the control calculator is capable of writing a result of calculation to the storage device and reading information from the storage device in accordance with the program. The outdoor control unit 39a also includes a timer.

[0055] The outdoor control unit 39a exchanges control signals, measurement signals, signals related to various settings, and the like with the indoor control units 29a and 29b of the indoor units 20a and 20b, the ventilation control unit 49 of the ventilator 40, and the control unit 13 of the air conditioning control apparatus 10 via the communication line 80.

[0056] The outdoor control unit 39a, the indoor control units 29a and 29b, and the ventilation control unit 49 cooperate to function as the controller C1. The function of the controller C1 will be described later.

(2-3) Ventilator

[0057] The ventilator 40 ventilates the target space SP in conjunction with the indoor unit 20a. In other words, the indoor unit 20a can perform the ventilation operation in conjunction with the ventilator 40. In the present embodiment, the ventilator 40 is provided in an attic 90 of the target space SP.

[0058] FIG. 3 is a schematic configuration diagram of the ventilator 40. FIG. 4 is a diagram illustrating an arrangement of the indoor unit 20a and the ventilator 40. As shown in FIG. 3, the ventilator 40 mainly includes an inlet duct 71, the air supply duct 72, an outlet duct 73, an exhaust duct 74, a device body 41, and the ventilation control unit 49.

[0059] The inlet duct 71 is connected to an inlet for taking the outdoor air OA into the target space SP. As shown in FIG. 4, the air supply duct 72 is connected to the indoor unit 20a that also serves as an air supply port for supplying the outdoor air OA to the target space SP as a supply air SA. The outlet duct 73 is connected to an outlet for taking out the indoor air RA from the target space SP. The exhaust duct 74 is connected to a discharge port for discharging the indoor air RA to the outside as a discharge air EA. The device body 41 is connected to the inlet duct 71, the air supply duct 72, the outlet duct 73, and the exhaust duct 74.

[0060] The device body 41 is provided with a ventilation heat exchanger 42, and two ventilation passages 43 and 44 partitioned from each other are formed so as to cross the ventilation heat exchanger 42. Here, the ventilation heat exchanger 42 is a total heat exchanger that simultaneously exchanges sensible heat and latent heat between two air flows (here, the indoor air RA and the outdoor air OA), and is provided across the ventilation passages 43 and 44. One ventilation passage 43 has one end connected to the inlet duct 71 and the other end connected to the air supply duct 72, and constitutes an air supply path for flowing air from the outside toward the target space SP via the indoor unit 20a. The other ventilation path 44 has one end connected to the outlet duct 73 and the other end connected to the exhaust duct 74, and constitutes an exhaust path for flowing air from the target space SP to the outside. The ventilation passage 43 is provided with an air supply fan 45 driven by an air supply fan motor 45m in order to generate an air flow from the outside toward the target space SP via the indoor unit 20a, and the ventilation passage 44 is provided with an exhaust fan 46 driven by an exhaust fan motor 46m in order to generate an air flow from the target space SP toward the outside. The air supply fan 45 and the exhaust fan 46 are disposed downstream of the ventilation heat exchanger 42 in the air flow.

[0061] The ventilation control unit 49 controls the operation of each unit constituting the ventilator 40.

[0062] The ventilation control unit 49 is electrically connected to various devices of the ventilator 40, which include the air supply fan motor 45m and the exhaust fan motor 46m.

[0063] The ventilation control unit 49 includes a control calculator and a storage device. The control calculator is a processor such as a CPU or a GPU. The storage device is a storage medium such as a RAM, a ROM, or a flash memory. The control calculator reads a program from the storage device and executes predetermined calculation processing in accordance with the program to control the operation of each component constituting the ventilator 40. In addition, the control calculator is capable of writing a result of calculation to the storage device and reading information from the storage device in accordance with the program. The ventilation control unit 49 also includes a timer.

[0064] The ventilation control unit 49 exchanges control signals, measurement signals, signals related to various settings, and the like with the indoor control units 29a and 29b of the indoor units 20a and 20b, the outdoor control unit 39a of the outdoor unit 30a, and the control unit 13 of the air conditioning control apparatus 10 via the communication line 80.

[0065] The ventilation control unit 49 the indoor control units 29a and 29b, and the outdoor control unit 39a cooperate to function as the controller C1. The function of the controller C1 will be described later.

(2-4) Controllers

[0066] In the present embodiment, the cooperation of the indoor control units 29a and 29b of the indoor units 20a and 20b, the outdoor control unit 39a of the outdoor unit 30a, and the ventilation control unit 49 of the ventilator 40 functions as the controller C1 that controls the operation of the refrigerant system RS1.

[0067] FIGS. 5A and 5B are control block diagrams of the air conditioning system 1. As illustrated in FIG. 5A, the controller C1 is communicably connected to the liquid-side temperature sensors 61a and 61b, the gas-side temperature sensors 62a and 62b, the indoor temperature sensors 63a and 63b, the human detection sensors 64a and 64b, the suction pressure sensor 65a, the discharge pressure sensor 66a, the heat exchange temperature sensor 67a, and the outdoor temperature sensor 68a. The controller C1 receives measurement signals transmitted from various sensors. The controller C1 is electrically connected to the indoor expansion valves 23a and 23b, the indoor fan motors 22am and 22bm, the compressor motor 31am, the flow direction switching mechanism 32a, the outdoor expansion valve 34a, the outdoor fan motor 36am, the air supply fan motor 45m, and the exhaust fan motor 46m. The controller C1 controls the operation of the devices of the refrigerant system RS1, which include the indoor expansion valves 23a and 23b, the indoor fan motors 22am and 22bm, the compressor motor 31am, the flow direction switching mechanism 32a, the outdoor expansion valve 34a, the outdoor fan motor 36am, the air supply fan motor 45m, and the exhaust fan motor 46m, on the basis of the measurement signals of the various sensors in accordance with the control signal transmitted from the operation remote controller of the refrigerant system RS1 and the control signal transmitted from the air conditioning control apparatus 10.

[0068] Similarly, the cooperation between the indoor control units 29c and 29d of the indoor units 20c and 20d and the outdoor control unit 39b of the outdoor unit 30b functions as a controller C2 that controls the operation of the refrigerant system RS2. As shown in FIG. 5B, the controller C2 is communicably connected to liquid-side temperature sensors 61c and 61d, gas-side temperature sensors 62c and 62d, indoor temperature sensors 63c and 63d, human detection sensors 64c and 64d, a suction pressure sensor 65b, a discharge pressure sensor 66b, a heat exchange temperature sensor 67b, and an outdoor temperature sensor 68b. The controller C2 receives measurement signals transmitted from various sensors. The controller C2 is electrically connected to indoor expansion valves 23c and 23d, indoor fan motors 22cm and 22dm, a compressor motor 31bm, a flow direction switching mechanism 32b, an outdoor expansion valve 34b, and an outdoor fan motor 36bm. The controller C2 controls the operation of the devices of the refrigerant system RS2, which include the indoor expansion valves 23c and 23d, the indoor fan motors 22cm and 22dm, the compressor motor 31bm, the flow direction switching mechanism 32b, the outdoor expansion valve 34b, and the outdoor fan motor 36bm, on the basis of the measurement signals of the various sensors in accordance with the control signal transmitted from the operation remote controller of the refrigerant system RS2 and the control signal transmitted from the air conditioning control apparatus 10.

[0069] The controller C1 controls various devices of the refrigerant system RS1 to cause the indoor units 20a and 20b to perform the cooling operation, the heating operation, the fan operation, and the ventilation operation. The cooling operation, the heating operation, the fan operation, and the ventilation operation that the controller C1 causes the indoor unit 20a to perform will be described below.

(2-4-1) Cooling Operation

[0070] When receiving an instruction to cause the indoor unit 20a to perform the cooling operation from the operation remote controller or the air conditioning control apparatus 10, the controller C1 controls the flow direction switching mechanism 32a to a state indicated by the solid line in FIG. 2 to set the state of the outdoor heat exchanger 33a to the second state of functioning as a condenser. Then, the controller C1 fully opens the outdoor expansion valve 34a, and adjusts the opening degree of the indoor expansion valve 23a to set a degree of superheating of the refrigerant at a gas-side outlet of the indoor heat exchanger 21a to a predetermined target degree of superheating. The degree of superheating of the refrigerant at the gas-side outlet of the indoor heat exchanger 21a is calculated, for example, by subtracting an evaporation temperature converted from a measurement value (suction pressure) of the suction pressure sensor 65a from a measurement value of the gas-side temperature sensor 62a.

[0071] The controller C1 controls an operating capacity of the compressor 31a to cause the evaporation temperature converted from the measurement value (suction pressure) of the suction pressure sensor 65a to approach a predetermined target evaporation temperature. The operating capacity of the compressor 31a is controlled by controlling the number of rotations of the compressor motor 31am.

[0072] When the operation of the devices is controlled as described above, the refrigerant flows through the refrigerant circuit 50 during the cooling operation as follows.

[0073] When the compressor 31a is started, a low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 31a and compressed by the compressor 31a to become a high-pressure gas refrigerant in the refrigeration cycle. The high-pressure gas refrigerant is sent to the outdoor heat exchanger 33a via the flow direction switching mechanism 32a, exchanges heat with heat source air supplied by the outdoor fan 36a, and is condensed into a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows through the liquid refrigerant pipe 54d and passes through the outdoor expansion valve 34a. The high-pressure liquid refrigerant sent to the indoor unit 20a is decompressed to near the suction pressure of the compressor 31a in the indoor expansion valve 23a, becomes a refrigerant in a gas-liquid two-phase state, and is sent to the indoor heat exchanger 21a. The refrigerant in the gas-liquid two-phase state exchanges heat with the air in the target space SP supplied to the indoor heat exchanger 21a by the indoor fan 22a in the indoor heat exchanger 21a and evaporates to become a low-pressure gas refrigerant. The low-pressure gas refrigerant is sent to the outdoor unit 30a via the gas refrigerant connection pipe 52, and flows into the accumulator 35a via the flow direction switching mechanism 32a. The low-pressure gas refrigerant flowing into the accumulator 35a is again sucked into the compressor 31a. On the other hand, the temperature of the air supplied to the indoor heat exchanger 21a decreases by heat exchange with the refrigerant flowing through the indoor heat exchanger 21a, and the air cooled by the indoor heat exchanger 21a is blown into the target space SR.

(2-4-2) Heating Operation

[0074] When receiving an instruction to cause the indoor unit 20a to perform the heating operation from the operation remote controller or the air conditioning control apparatus 10, the controller C1 controls the flow direction switching mechanism 32a to a state indicated by the broken line in FIG. 2 to set the state of the outdoor heat exchanger 33a to the first state of functioning as an evaporator. Then, the controller C1 adjusts the opening degree of the indoor expansion valve 23a to set a degree of subcooling of the refrigerant at a liquid-side outlet of the indoor heat exchanger 21a to a predetermined target degree of subcooling. The degree of subcooling of the refrigerant at the liquid-side outlet of the indoor heat exchanger 21a is calculated, for example, by subtracting a measurement value of the liquid-side temperature sensor 61a from a condensation temperature converted from a measurement value (discharge pressure) of the discharge pressure sensor 66a.

[0075] The controller C1 also adjusts the opening degree of the outdoor expansion valve 34a to decompress the refrigerant flowing into the outdoor heat exchanger 33a to a pressure at which the refrigerant can evaporate in the outdoor heat exchanger 33a.

[0076] The controller C1 controls an operating capacity of the compressor 31a to cause the condensation temperature converted from the measurement value (discharge pressure) of the discharge pressure sensor 66a to approach a predetermined target condensation temperature. The operating capacity of the compressor 31a is controlled by controlling the number of rotations of the compressor motor 31am.

[0077] When the operation of the devices is controlled as described above, the refrigerant flows through the refrigerant circuit 50 during the heating operation as follows.

[0078] When the compressor 31a is started, a low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 31a and compressed by the compressor 31a to become a high-pressure gas refrigerant in the refrigeration cycle. The high-pressure gas refrigerant is sent to the indoor heat exchanger 21a via the flow direction switching mechanism 32a, exchanges heat with the air in the target space SP supplied by the indoor fan 22a, and is condensed into a high-pressure liquid refrigerant. The temperature of the air supplied to the indoor heat exchanger 21a rises by heat exchange with the refrigerant flowing through the indoor heat exchanger 21a, and the air heated by the indoor heat exchanger 21a is blown into the target space SP. The high-pressure liquid refrigerant having passed through the indoor heat exchanger 21a passes through the indoor expansion valve 23a to be decompressed. The refrigerant decompressed in the indoor expansion valve 23a is sent to the outdoor unit 30a via the liquid refrigerant connection pipe 51, and flows into the liquid refrigerant pipe 54d. The refrigerant flowing through the liquid refrigerant pipe 54d is decompressed to near the suction pressure of the compressor 31a when passing through the outdoor expansion valve 34a, becomes the refrigerant in the gas-liquid two-phase state, and flows into the outdoor heat exchanger 33a. The low-pressure refrigerant in the gas-liquid two-phase state that has flowed into the outdoor heat exchanger 33a exchanges heat with the heat source air supplied by the outdoor fan 36a, evaporates to become a low-pressure gas refrigerant, and flows into the accumulator 35a via the flow direction switching mechanism 32a. The low-pressure gas refrigerant flowing into the accumulator 35a is again sucked into the compressor 31a.

(2-4-3) Fan Operation

[0079] When receiving an instruction to cause the indoor unit 20a to perform the fan operation from the operation remote controller or the air conditioning control apparatus 10, the controller C1 fully closes the indoor expansion valve 23a. Then, the controller C1 controls the indoor fan motor 22am so as to have a predetermined target air volume, sucks the indoor air RA of the target space SP into the indoor unit 20a, and supplies the sucked indoor air RA to the target space SP again. As a result, the indoor air RA in the target space SP is stirred or circulated.

(2-4-4) Ventilation Operation

[0080] When receiving an instruction to cause the indoor unit 20a to perform the ventilation operation from the operation remote controller or the air conditioning control apparatus 10, the controller C1 causes the indoor unit 20 a to perform the fan operation with a low air volume and activates the air supply fan 45 and the exhaust fan 46 of the ventilator 40. Then, the outdoor air OA flowing into the device body 41 from the outside through the inlet duct 71 and the indoor air RA flowing into the device body 41 from the target space SP through the outlet duct 73 exchange heat in the ventilation heat exchanger 42. Next, the outdoor air OA having exchanged heat in the ventilation heat exchanger 42 is supplied as the supply air SA from the device body 41 to the target space SP via the indoor unit 20a through the air supply duct 72. The indoor air RA having exchanged heat in the ventilation heat exchanger 42 is discharged as the discharge air EA from the device body 41 to the outside through the exhaust duct 74.

(2-5) Air Conditioning Control Apparatus

[0081] The air conditioning control apparatus 10 controls the indoor units 20a to 20d, the outdoor units 30a and 30b, and the ventilator 40 to execute various operations and various functions. As shown in FIG. 5A, the air conditioning control apparatus 10 mainly includes a storage unit 11, an input-output unit 12, and the control unit 13.

(2-5-1) Storage Unit

[0082] The storage unit 11 is a storage device such as a RAM, a ROM, or a hard disk drive (HDD). The storage unit 11 stores a program executed by the control unit 13, data necessary for executing the program, and the like.

(2-5-2) Input-Output Unit

[0083] The input-output unit 12 is a touch panel display for inputting and outputting information to and from the air conditioning control apparatus 10. A user can input various types of information and execute various operations and various functions by tapping, sliding, and the like on the display with a finger, for example. In addition, the input-output unit 12 can display operation statuses and the like of the indoor units 20a to 20d, the outdoor units 30a and 30b, and the ventilator 40.

(2-5-3) Control Unit

[0084] The control unit 13 is a calculation processor such as a CPU. As shown in FIG. 5A, the control unit 13 reads and executes a program stored in the storage unit 11 to implement various functions of the air conditioning control apparatus 10. The control unit 13 can also write a calculation result to the storage unit 11 and read information stored in the storage unit 11 in accordance with the program.

[0085] As shown in FIGS. 5A and 5B, the control unit 13 exchanges control signals, measurement signals, signals related to various settings, and the like with the indoor control units 29a to 29d of the indoor units 20a to 20d, the outdoor control units 39a and 39b of the outdoor units 30a and 30b, and the ventilation control unit 49 of the ventilator 40 via the communication line 80. Then, the control unit 13 controls the indoor units 20a to 20d, the outdoor units 30a and 30b, and the ventilator 40 in cooperation with the controllers C1 and C2. In particular, the control unit 13 can cause the indoor units 20a to 20d to perform the cooling operation, the heating operation, the fan operation, or the ventilation operation.

[0086] As shown in FIG. 5A, the control unit 13 has a grouping function and a thermal load adjustment function as main functions.

(2-5-3-1) Group Setting Function

[0087] A group setting function is a function of setting a group GP of the indoor units to be subjected to the thermal load adjustment function. The control unit 13 sets the indoor unit designated by using the input-output unit 12 among the indoor units 20a to 20d as one group GP (indoor unit group). For example, the control unit 13 may set all the indoor units 20a to 20d as one group GP. The control unit 13 may also set, for example, some of the indoor units 20a to 20d such as the indoor unit 20a and the indoor unit 20b as one group GP. The control unit 13 may also set, as one group GP, indoor units belonging to different refrigerant systems, such as the indoor unit 20a and the indoor unit 20c, for example. As shown in FIG. 1, the present embodiment will be described on the assumption that the indoor units 20a to 20c are set as one group GP1.

(2-5-3-2) Thermal Load Adjustment Function

[0088] The thermal load adjustment function is a function of eliminating a difference between thermal loads when a difference of a certain level or more occurs in thermal loads to be processed by each of the indoor units 20a to 20c belonging to the group GP1.

[0089] Hereinafter, the processing of the thermal load adjustment function will be described with reference to a flowchart of FIG. 6. As an assumption, the indoor units 20a to 20c are performing the cooling operation or the heating operation.

[0090] As shown in step S1, the control unit 13 starts the thermal load adjustment function by an instruction from the input-output unit 12 or the like.

[0091] When step S1 ends and the processing proceeds to step S2, the control unit 13 stands by for a predetermined time T1.

[0092] When step S2 ends and the processing proceeds to step S3, the control unit 13 determines whether a difference of a certain level or more occurs in thermal loads to be processed by each of the indoor units 20a to 20c. In the present embodiment, the thermal load to be processed by each of the indoor units 20a to 20c is determined on the basis of a temperature difference δT between a set temperature and a room temperature of each of the indoor units 20a to 20c. Specifically, it is regarded that the larger the temperature difference ST, the larger the thermal load. The room temperature can be acquired from measurement values of the indoor temperature sensors 63a to 63c of the indoor units 20a to 20c. Therefore, in step S3, the control unit 13 determines whether there is a difference of a certain level or more between a maximum value and a minimum value of the temperature differences δT of the indoor units 20a to 20c. Here, the “difference of a certain level or more” is, for example, 5° C. For example, when the temperature differences δT of the indoor units 20a to 20c are 2° C., 1° C., and 6° C., respectively, since there is a difference of 5° C. or more between the temperature difference δT (minimum value) of the indoor unit 20b and the temperature difference δT (maximum value) of the indoor unit 20c, the control unit 13 determines that a difference of a certain level or more occurs in thermal loads to be processed by each of the indoor units 20a to 20c. In step S3, when there is a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT, the processing proceeds to step S4. In step S3, when there is not a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT, the processing returns to step S2, and the control unit 13 stands by for the predetermined time T1 again. In other words, the control unit 13 determines whether there is a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT of the indoor units 20a to 20c every predetermined time T1.

[0093] When step S3 ends and the processing proceeds to step S4, the control unit 13 divides the indoor units 20a to 20c into a first indoor unit and a second indoor unit. In the present embodiment, the control unit 13 divides the indoor units 20a to 20c into the first indoor unit and the second indoor unit so that the second indoor unit has a smaller thermal load to be processed than the first indoor unit. In the present embodiment, the control unit 13 sets the indoor unit having the largest thermal load to be processed as the first indoor unit, and sets the other indoor units as the second indoor units. Therefore, in step S4, the control unit 13 sets the indoor unit having the largest temperature difference δT among the indoor units 20a to 20c as the first indoor unit, and sets the other indoor units as the second indoor units. In the above example, the indoor unit 20c is the first indoor unit, and the indoor units 20a and 20b are the second indoor units.

[0094] When step S4 ends and the processing proceeds to step S5, the control unit 13 causes the first indoor unit to perform the cooling operation or the heating operation. Since the first indoor unit has a relatively large thermal load to be processed, the control unit 13 causes the first indoor unit to perform the cooling operation or the heating operation to actively process the thermal load. In the present embodiment, the control unit 13 causes the first indoor unit currently performing the cooling operation to continuously perform the cooling operation. The control unit 13 causes the first indoor unit currently performing the heating operation to continuously perform the heating operation. In the above example, the control unit 13 causes the indoor unit 20c to continuously perform the cooling operation or the heating operation.

[0095] In step S5, the control unit 13 causes the second indoor unit to perform the fan operation or the ventilation operation. Since the second indoor unit has a relatively small thermal load to be processed, the control unit 13 causes the second indoor unit to perform the fan operation or the ventilation operation, and stirs or circulates the indoor air RA in the target space SP to assist thermal load processing performed by the first indoor unit. In the present embodiment, when the second indoor unit cannot perform the ventilation operation, the control unit 13 causes the second indoor unit to perform the fan operation. When the second indoor unit can perform the ventilation operation, the control unit 13 causes the second indoor unit to perform the ventilation operation if the set temperature of the second indoor unit and the outdoor temperature are within a predetermined range, and causes the second indoor unit to perform the fan operation otherwise. The outdoor temperature can be acquired from a measurement value of the outdoor temperature sensor 68a. In the above example, since the indoor unit 20a can perform the ventilation operation, the control unit 13 causes the indoor unit 20a to perform the ventilation operation if the set temperature of the indoor unit 20a and the outdoor temperature are within the predetermined range, and causes the indoor unit 20a to perform the fan operation otherwise. Since the indoor unit 20b cannot perform the ventilation operation, the control unit 13 causes the indoor unit 20b to perform the fan operation. At this time, in order to further stir or circulate the indoor air RA in the target space SP, the control unit 13 may cause the second indoor unit to perform the fan operation or the ventilation operation with an air volume higher than an air volume during an operation before the fan operation or the ventilation operation is performed.

[0096] When step S5 ends and the processing proceeds to step S6, the control unit 13 stands by for a predetermined time T2.

[0097] When step S6 ends and the processing proceeds to step S7, the control unit 13 determines whether there is a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT of the indoor units 20a to 20c. When there is a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT, the processing returns to step S6, and the control unit 13 stands by for the predetermined time T2 again. In other words, the control unit 13 determines whether there is a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT of the indoor units 20a to 20c every predetermined time T2. When there is not a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT, the processing proceeds to step S8.

[0098] When step S7 ends and the processing proceeds to step S8, the control unit 13 switches the fan operation or the ventilation operation performed by the second indoor unit to the operation before the fan operation or the ventilation operation is performed. In the above example, the control unit 13 switches the fan operation or the ventilation operation performed by the indoor units 20a and 20b to the operation before the fan operation or the ventilation operation is performed.

[0099] When step S8 ends and the processing proceeds to step S2, the control unit 13 determines whether there is a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT of the indoor units 20a to 20c every predetermined time T1 again.

[0100] The control unit 13 repeats this processing until the thermal load adjustment function is stopped by an instruction from the input-output unit 12 or the like. When the thermal load adjustment function is stopped, the control unit 13, for example, switches the fan operation or the ventilation operation performed by the second indoor unit to the operation before the fan operation or the ventilation operation is performed.

(3) Characteristics

(3-1)

[0101] There is a conventional technique for controlling a circulation amount of the refrigerant to be equal between the indoor units when there is an extreme difference in a distribution ratio of the refrigerant between the indoor units in order to adjust the circulation amount of the refrigerant and improve a non-uniform temperature distribution in the space. However, there is a problem that the non-uniform temperature distribution in the space cannot be sufficiently improved by simply adjusting the circulation amount of the refrigerant because warm air is accumulated on an upper side and cold air is accumulated on a lower side.

[0102] The air conditioning control apparatus 10 according to the present embodiment controls the plurality of indoor units 20a to 20d. The air conditioning control apparatus 10 sets the indoor units 20a to 20c having been designated among the plurality of indoor units 20a to 20d as one group GP1. The air conditioning control apparatus 10 causes the first indoor unit belonging to the group GP1 to perform the cooling operation or the heating operation and causes the second indoor unit belonging to the group GP1 to perform the fan operation or the ventilation operation when a difference of a certain level or more occurs in thermal loads to be processed by each of the indoor units 20a to 20c belonging to the group GP1.

[0103] The air conditioning control apparatus 10 according to the present embodiment causes the second indoor unit to perform the fan operation or the ventilation operation when a difference of a certain level or more occurs in thermal loads to be processed by each of the indoor units 20a to 20c belonging to the group GP1. As a result, the air conditioning control apparatus 10 can improve the non-uniform temperature distribution in the target space SP by stirring the indoor air RA in the target space SP.

(3-2)

[0104] The air conditioning control apparatus 10 according to the present embodiment causes the first indoor unit to perform the cooling operation or the heating operation and causes the second indoor unit to perform the fan operation or the ventilation operation on the basis of the temperature difference δT between the set temperature and the room temperature of each of the indoor units 20a to 20c belonging to the group GP1.

[0105] As a result, on the basis of the temperature difference δT between the set temperature and the room temperature of each of the indoor units 20a to 20c, the air conditioning control apparatus 10 can easily know the thermal load to be processed by each of the indoor units 20a to 20c, and can cause the second indoor unit to perform the fan operation or the ventilation operation.

(3-3)

[0106] In the air conditioning control apparatus 10 according to the present embodiment, the thermal load to be processed by the second indoor unit is smaller than the thermal load to be processed by the first indoor unit.

[0107] As a result, the air conditioning control apparatus 10 stirs the indoor air RA in the target space SP by using the indoor unit with a smaller thermal load to be processed while continuing the operation of the indoor unit with a larger thermal load, and thus, can improve the non-uniform temperature distribution in the target space SR.

(3-4)

[0108] The air conditioning control apparatus 10 according to the present embodiment causes the second indoor unit to perform the fan operation or the ventilation operation with the air volume higher than the air volume during an operation before the fan operation or the ventilation operation is performed.

[0109] As a result, the air conditioning control apparatus 10 can further improve the non-uniform temperature distribution in the target space SP by further stirring the indoor air RA in the target space SP.

(3-5)

[0110] The air conditioning control apparatus 10 according to the present embodiment switches the fan operation or the ventilation operation performed by the second indoor unit to the operation before the fan operation or the ventilation operation is performed, on the basis of the temperature difference δT between the set temperature and the room temperature of the second indoor unit or the thermal load to be processed by each of the indoor units 20a to 20c other than the second indoor unit and belonging to the group GP1.

[0111] As a result, after the non-uniform temperature distribution in the target space SP is improved, the air conditioning control apparatus 10 can cause the second indoor unit to return to the operation before the fan operation or the ventilation operation is performed.

(3-6)

[0112] The air conditioning system 1 according to the present embodiment includes the air conditioning control apparatus 10 and the plurality of indoor units 20a to 20d.

(4) Modifications

(4-1) Modification 1A

[0113] In the present embodiment, the air conditioning system 1 includes four indoor units 20a to 20d, two outdoor units 30a and 30b, and one ventilator 40. The air conditioning system 1 has two refrigerant systems RS1 and RS2.

[0114] However, the configuration of the air conditioning system 1 is arbitrary, and for example, the air conditioning system 1 may include more devices and more refrigerant systems.

(4-2) Modification 1B

[0115] In the present embodiment, for convenience, the indoor unit 20a is in conjunction with the ventilator 40 in order to cause the indoor unit 20a to perform the ventilation operation. Alternatively, the ventilator 40 may be in conjunction with any of the indoor units 20a to 20d.

(4-3) Modification 1C

[0116] In the present embodiment, in the air conditioning control apparatus 10, the thermal load to be processed by each of the indoor units 20a to 20c belonging to the group GP1 is determined on the basis of the temperature difference δT between the set temperature and the room temperature of each of the indoor units 20a to 20c.

[0117] Alternatively, the air conditioning control apparatus 10 may determine the thermal load to be processed by each of the indoor units 20a to 20c on the basis of a target condensation temperature (in the case of the heating operation) or a target evaporation temperature (in the case of the cooling operation) requested by each of the indoor units 20a to 20c to each of the outdoor units 30a and 30b to which the indoor units 20a to 20c are respectively connected. In other words, the air conditioning control apparatus 10 causes the first indoor unit to perform the cooling operation or the heating operation and causes the second indoor unit to perform the fan operation or the ventilation operation on the basis of the target condensation temperature (in the case of the heating operation) or the target evaporation temperature (in the case of the cooling operation) requested by each of the indoor units 20a to 20c to each of the outdoor units 30a and 30b to which the indoor units 20a to 20c are respectively connected. The indoor units 20a to 20c belonging to the group GP1 form a refrigeration cycle together with the outdoor units 30a and 30b. For example, when the indoor units 20a to 20c are performing the cooling operation, the air conditioning control apparatus 10 determines the thermal load to be processed by each of the indoor units 20a to 20c on the basis of a temperature difference between the evaporation temperature converted from the current measurement values (suction pressures) of the suction pressure sensors 65a and 65b and the target evaporation temperature. In this case, it is considered that the larger the temperature difference, the larger the thermal load.

[0118] As a result, on the basis of the condensation temperature or the evaporation temperature required by each of the indoor units 20a to 20c to each of the outdoor units 30a and 30b, the air conditioning control apparatus 10 can more accurately know the thermal load to be processed by each of the indoor units 20a to 20c, and can cause the second indoor unit to perform the fan operation or the ventilation operation.

(4-4) Modification 1D

[0119] In the present embodiment, the air conditioning control apparatus 10 determines whether there is a difference of a certain level or more between the maximum value and the minimum value of the temperature differences δT of the indoor units 20a to 20c belonging to the group GP1.

[0120] However, for example, the air conditioning control apparatus 10 may determine whether there is a variance of a certain level or more between the temperature differences δT of the indoor units 20a to 20c.

(4-5) Modification 1E

[0121] In the present embodiment, the air conditioning control apparatus 10 sets the indoor unit having the largest thermal load to be processed as the first indoor unit, and sets the other indoor units as the second indoor units.

[0122] However, the air conditioning control apparatus 10 may set a predetermined number of indoor units as the first indoor unit and set the other indoor units as the second indoor unit, for example, in the order of a larger thermal load to be processed.

(4-6) Modification 1F

[0123] The air conditioning control apparatus 10 may have a function (automatic stop function) of automatically stopping the cooling operation or the heating operation of the indoor units 20a to 20d in accordance with the set temperature. Specifically, while the indoor units 20a to 20d are performing the cooling operation, the air conditioning control apparatus 10 automatically stops the cooling operation of the indoor units 20a to 20d when the room temperature falls below the set temperature and the temperature difference between the set temperature and the room temperature becomes larger than a predetermined threshold value (when an automatic stop condition is satisfied). While the indoor units 20a to 20d are performing the heating operation, the air conditioning control apparatus 10 automatically stops the heating operation of the indoor units 20a to 20d when the room temperature exceeds the set temperature and the temperature difference between the set temperature and the room temperature becomes larger than a predetermined threshold value (when an automatic stop condition is satisfied). The predetermined threshold value is, for example, 2° C. In other words, in any one of the indoor units 20a to 20d, when the automatic stop condition is satisfied, it can be said that a difference of a certain level or more occurs in thermal loads to be processed by each of the indoor units 20a to 20d. In this case, the indoor unit satisfying the automatic stop condition is an indoor unit having a small thermal load to be processed.

[0124] Therefore, the air conditioning control apparatus 10 may use the automatic stop function to set the indoor unit that satisfies the automatic stop condition as the second indoor unit. In this case, the air conditioning control apparatus 10 does not stop the operation of the indoor unit that satisfies the automatic stop condition, but causes the indoor unit that satisfies the automatic stop condition to perform the fan operation or the ventilation operation.

[0125] As a result, the air conditioning control apparatus 10 can cause the second indoor unit to perform the fan operation or the ventilation operation by using the automatic stop function.

(4-7) Modification 1G

[0126] The air conditioning control apparatus 10 may perform learning for determining the first indoor unit and the second indoor unit so as to reduce a total power consumption of the group GP1. The total power consumption of the group GP1 is, for example, a sum of power consumption of the indoor units 20a to 20c belonging to the group GP1. For example, the air conditioning control apparatus 10 uses, as the power consumption of the indoor units 20a and 20b, power consumption of the compressor 31a of the outdoor unit 30a distributed by the opening degrees of the indoor expansion valves 23a and 23b. For example, the air conditioning control apparatus 10 may determine the first indoor unit and the second indoor unit while performing deep reinforcement learning with the total power consumption of the group GP1 being reduced as a reward.

[0127] As a result, the air conditioning control apparatus 10 can improve the non-uniform temperature distribution in the target space SP and reduce the total power consumption of the group GP1.

(4-8) Modification 1H

[0128] The air conditioning control apparatus 10 may learn a start time of the cooling operation or the heating operation of the indoor units 20a to 20c belonging to the group GP1, and may automatically start the cooling operation or the heating operation before the predicted start time. For the learning, for example, a recursive neural network, a state space model, or the like is used.

[0129] As a result, the air conditioning control apparatus 10 can cause the thermal load to be processed in advance by automatically starting the cooling operation or the heating operation before the predicted start time.

(4-9) Modification 1I

[0130] The air conditioning control apparatus 10 may include a human detector as a functional block. The human detector detects a person in the target space SP by using human detection sensors 64a to 64d. When there is no person in the target space SP, the air conditioning control apparatus 10 causes at least one indoor unit belonging to the group GP1 to perform the fan operation or the ventilation operation to circulate the indoor air RA in the target space SP.

[0131] As a result, the air conditioning control apparatus 10 can improve the non-uniform temperature distribution in the target space SP by circulating the indoor air RA in the target space SP while there is no person in the target space SP.

(4-10) Modification 1J

[0132] The air conditioning control apparatus 10 may have a function of equalizing the set temperatures of the indoor units 20a to 20c belonging to the group GP1 if a predetermined condition is satisfied. For example, when the difference between a maximum value and a minimum value of measured values of the indoor temperature sensors 63a to 63c is larger than a predetermined value, the air conditioning control apparatus 10 sets the set temperatures of the indoor units 20a to 20c to an average value of the set temperatures. The predetermined value is, for example, 2° C.

[0133] As a result, the air conditioning control apparatus 10 can further improve the non-uniform temperature distribution in the target space SP by using both the function of equalizing the set temperatures of the indoor units 20a to 20c belonging to the group GP1 and the thermal load adjustment function.

(4-11)

[0134] The embodiment of the present disclosure has been described above. It will be understood that various changes to modes and details can be made without departing from the spirit and scope of the present disclosure recited in the claims.

• • [0135] 1: air conditioning system
  • [0136] 10: air conditioning control apparatus
  • [0137] 20a to 20d: indoor units
  • [0138] 30a, 30b: outdoor unit
  • [0139] GP, GP1: group (indoor unit group)
  • [0140] SP: target space (space)
  • [0141] δT: temperature difference

• [0142] Patent Literature 1: JP H05-312378 A