Multi-air conditioning system

Abstract

To provide a multi-air conditioning system capable of relaxing restriction of a total of respective connection capacities of an outside air processing unit and an indoor unit to an outdoor unit.SOLUTION: In the multi-air conditioning system, the outdoor air processing unit 2 and the three indoor units 3 are connected in parallel to the outdoor unit 1 by a refrigerant flow path 5 through which a refrigerant flows. The sum of the total connection capacity of the outdoor air processing units 2 to the outdoor unit 1 and the total connection capacity of the indoor units 3 to the outdoor unit 1 exceeds the heat processing capacity of the outdoor unit 1. The monitoring device 4 determines whether or not it is necessary to limit the operation based on indoor operation information that changes in accordance with a change in the thermal load amount during the operation of each indoor unit 3. The monitoring device 4 forcibly brings the state of the outside air processing unit 2 into a thermo-off state when determining that the operation needs to be limited.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a multi-air conditioning system. [Background technology]

[0002] In a multi-air conditioning system where multiple indoor units are connected in parallel to an outdoor unit, it is rare for all of the indoor units to operate simultaneously, so the total capacity of the multiple indoor units in a multi-air conditioning system is allowed to be greater than the capacity of the outdoor unit.

[0003] Patent Document 1 proposes a multi-air conditioning system that limits the operating capacity ratio of indoor units that are simultaneously thermo-on during heating, and forcibly switches indoor units to the thermo-off state in order of the indoor unit's required frequency ratio.As a result, the conventional multi-air conditioning system disclosed in Patent Document 1 operates in consideration of the heating requirement of each indoor unit while preventing overload operation of the outdoor unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-144939 Summary of the Invention [Problem to be solved by the invention]

[0005] In a multi-air conditioning system, an outdoor air processing unit including a direct expansion coil as an outdoor air processing unit heat exchanger may be connected in parallel to the outdoor unit and the indoor unit. In this case, the outdoor air processing unit needs to adjust the temperature of the outdoor air according to the temperature of the indoor air in order to supply the outdoor air taken in from the outside to the room. Therefore, the thermal load of the outdoor air processing unit may be higher than the thermal load of the indoor unit, which may limit the connection capacity of the outdoor air processing unit to the outdoor unit.

[0006] For example, if the total connection capacity of the outdoor air processing unit and multiple indoor units is allowed to be up to 130% of the capacity of the outdoor unit, and the total connection capacity of the multiple indoor units exceeds 100% of the capacity of the outdoor unit, the connection capacity of the outdoor air processing unit will be limited to less than 30% of the capacity of the outdoor unit.

[0007] The present disclosure aims to solve the above-mentioned problems and to provide a multi-air conditioning system that can relax the restrictions on the total connection capacity of the outdoor air processing unit and the indoor units to the outdoor unit. [Means for solving the problem]

[0008] The multi-air conditioning system according to the present disclosure comprises an outdoor unit, one or more outdoor air processing units that supply outdoor air drawn in from outside to a room as intake air and discharge air drawn in from inside the room to the outside as exhaust air, one or more indoor units that adjust the temperature of the air drawn in from inside the room and supply the adjusted air to the room, and a monitoring device, the one or more outdoor air processing units and the one or more indoor units are each connected in parallel to the outdoor unit by a refrigerant flow path through which a refrigerant flows, the one or more outdoor air processing units have a total heat exchanger, an outdoor air processing unit heat exchanger, and a humidifier, the total heat exchanger is capable of total heat exchange between the outdoor air drawn in by the outdoor air processing unit from outside and the air drawn in by the outdoor air processing unit from inside the room, and the outdoor air processing unit heat exchanger is configured to exchange total heat between the outdoor air drawn in by the outdoor air processing unit from outside and the air drawn in by the outdoor air processing unit Heat can be exchanged between the refrigerant and the outdoor air that has passed through the total heat exchanger, the humidifier can humidify the outdoor air that has passed through the outdoor air processing unit heat exchanger, one or more indoor units have an indoor unit heat exchanger that can exchange heat between the refrigerant flowing through the indoor unit heat exchanger and the air drawn in from inside the room by the indoor unit, the total connection capacity of the one or more outdoor air processing units to the outdoor unit and the total connection capacity of the one or more indoor units to the outdoor unit exceeds the heat processing capacity of the outdoor unit, and the monitoring device determines whether operation restriction is necessary based on indoor operation information that changes in accordance with changes in the heat load during operation of the one or more indoor units, and when a restriction determination is made that operation restriction is necessary, the monitoring device forcibly switches the state of the one or more outdoor air processing units to the thermo-off state. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to relax the restrictions on the total connection capacity of the outdoor air processing units and the indoor units to the outdoor unit. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a configuration diagram showing a multi-air conditioning system according to a first embodiment. [Figure 2] FIG. 2 is a configuration diagram showing a refrigerant circuit of the multi-air conditioning system of FIG. [Figure 3] FIG. 2 is a configuration diagram showing the outside air processing unit of FIG. 1. [Figure 4] 2 is a flowchart showing the processing operation of the monitoring device of FIG. 1. [Figure 5] 10 is a flowchart showing the processing operation of the monitoring device according to the second embodiment. [Figure 6] 11 is a flowchart showing the processing operation of the monitoring device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes embodiments of the subject matter of the present disclosure with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant explanations are appropriately simplified or omitted. Note that the subject matter of the present disclosure is not limited to the following embodiments, and any component of the embodiments may be modified or omitted within the scope of the gist of the present disclosure.

[0012] Embodiment 1 FIG. 1 is a configuration diagram showing a multi-air conditioning system according to embodiment 1. The multi-air conditioning system conditions the air indoors in a building. The multi-air conditioning system has an outdoor unit 1, one or more outdoor air processing units 2, one or more indoor units 3, and a monitoring device 4. In this embodiment, the multi-air conditioning system includes one outdoor air processing unit 2 and three indoor units 3.

[0013] The outdoor air processing unit 2 supplies outdoor air (OA), which is air drawn in from outside the building, i.e., from outside the room, to the room as supply air (SA). The outdoor air processing unit 2 also discharges return air (RA), which is air drawn in from inside the room, to the outside as exhaust air (EA). The outdoor air processing unit 2 adjusts at least one of the temperature and humidity of the outdoor air OA drawn in from outside the room, and supplies the adjusted outdoor air to the room as supply air SA. Each indoor unit 3 adjusts the temperature of the air drawn in from inside the room and supplies the adjusted air to the room.

[0014] The outdoor air processing unit 2 and each indoor unit 3 are connected in parallel to the outdoor unit 1 by refrigerant flow paths 5 through which the refrigerant flows. As a result, the outdoor unit 1, the outdoor air processing unit 2, and each indoor unit 3 form a refrigerant circuit in which the refrigerant circulates while changing phases.

[0015] The outdoor unit 1 is located outdoors. In a multi-air conditioning system, the outdoor unit 1 functions as a heat source unit for the outdoor air processing unit 2 and each of the indoor units 3 by circulating the refrigerant through the refrigerant circuit while changing phases.

[0016] An outdoor air processing remote control 20 and an indoor unit remote control 30 are provided indoors. The outdoor air processing unit 2 is operated based on commands generated by operating the outdoor air processing remote control 20. The indoor units 3 are operated based on commands generated by operating the indoor unit remote control 30. In this embodiment, the indoor unit remote control 30 serves as a common remote control for the three indoor units 3.

[0017] The monitoring device 4 monitors the operation of the outdoor air processing unit 2 and each of the indoor units 3.

[0018] Fig. 2 is a configuration diagram showing the refrigerant circuit of the multi-air conditioning system of Fig. 1. Fig. 3 is a configuration diagram showing the outdoor air processing unit 2 of Fig. 1. In Fig. 2, configurations other than those related to the refrigerant circuit in the outdoor air processing unit 2 are omitted. The outdoor air processing unit 2 has a casing 21, an intake air blower 22, an exhaust air blower 23, a total heat exchanger 24, an outdoor air processing unit heat exchanger 25, an outdoor air unit expansion valve 26, a humidifier 27, and an outdoor air unit control unit 28. The intake air blower 22, the exhaust air blower 23, the total heat exchanger 24, the outdoor air processing unit heat exchanger 25, and the humidifier 27 are arranged inside the casing 21.

[0019] As shown in Fig. 3, the casing 21 has a first side surface 21a and a second side surface 21b facing each other. An outside air inlet 211 and an exhaust air outlet 212 are provided on the first side surface 21a of the casing 21. An supply air outlet 213 and an indoor air inlet 214 are provided on the second side surface 21b of the casing 21. The outside air inlet 211 and the exhaust air outlet 212 are each connected to the outside of the room via a duct (not shown). The supply air outlet 213 and the indoor air inlet 214 are each connected to the inside of the room via a duct (not shown).

[0020] An intake air duct 215 and an exhaust air duct 216 are formed inside the casing 21. The intake air duct 215 is an air duct that guides outside air OA from the outside air inlet 211 to the intake air outlet 213 inside the casing 21. The intake air duct 215 passes from the outside air inlet 211 through the total heat exchanger 24, the outside air processing unit heat exchanger 25, and the humidifier 27 in this order, before reaching the intake air outlet 213. The exhaust air duct 216 is an air duct that guides return air RA from the indoor air inlet 214 to the exhaust air outlet 212 inside the casing 21. A part of the exhaust air duct 216 runs from the indoor air inlet 214 through the total heat exchanger 24 to reach the exhaust air outlet 212.

[0021] The intake air blower 22 is arranged in the intake air duct 215. In this embodiment, the intake air blower 22 is arranged in the section of the intake air duct 215 between the total heat exchanger 24 and the outside-air processing unit heat exchanger 25.

[0022] The intake air blower 22 generates a flow of air from the outside to the inside of the room. As a result, when the intake air blower 22 operates, outside air OA is drawn from the outside into the intake air duct 215 through the duct and the outside air inlet 211. The outside air OA drawn into the intake air duct 215 flows through the intake air duct 215, and is then supplied into the room as intake air SA from the intake air outlet 213 through the duct.

[0023] The exhaust fan 23 is disposed in the exhaust air duct 216. In the present embodiment, the exhaust fan 23 is disposed in the section of the exhaust air duct 216 between the total heat exchanger 24 and the exhaust outlet 212.

[0024] The exhaust fan 23 generates a flow of air from the room to the outside. As a result, when the exhaust fan 23 operates, indoor air is drawn from the room as return air RA through the duct and the indoor air inlet 214 into the exhaust air duct 216. The return air RA drawn into the exhaust air duct 216 flows through the exhaust air duct 216, and then passes through the exhaust outlet 212 and the duct to be discharged to the outside as exhaust air EA. Therefore, the outside air processing unit 2 ventilates the room by operating the intake air fan 22 and the exhaust fan 23.

[0025] A switching damper 217 is provided in the exhaust air passage 216. The switching damper 217 is displaceable between a normal position and a bypass position. When the switching damper 217 is in the normal position, air drawn from the indoor air inlet 214 into the exhaust air passage 216 as return air RA passes through the total heat exchanger 24 and is guided to the exhaust air outlet 212. When the switching damper 217 is in the bypass position, air drawn from the indoor air inlet 214 into the exhaust air passage 216 as return air RA avoids the total heat exchanger 24, flows through the exhaust air passage 216, and is guided to the exhaust air outlet 212.

[0026] The total heat exchanger 24 is stacked with an intake air passage layer in which an intake heat exchange passage (not shown) is formed and an exhaust air passage layer in which an exhaust heat exchange passage (not shown) is formed. In this embodiment, when the total heat exchanger 24 is viewed along the stacking direction of the intake air passage layer and the exhaust air passage layer, the direction along the intake air heat exchange passage and the direction along the exhaust air heat exchange passage are perpendicular to each other.

[0027] When the switching damper 217 is in the normal position, the return air RA flows through the exhaust heat exchange duct of the total heat exchanger 24. In the total heat exchanger 24, total heat exchange occurs between the outside air OA flowing through the supply air heat exchange duct and the return air RA flowing through the exhaust heat exchange duct. That is, the total heat exchanger 24 is capable of total heat exchange between the outside air OA, which is air drawn in from outside the room by the outside air processing unit 2, and the return air RA, which is air drawn in from inside the room by the outside air processing unit 2. As a result, sensible heat and latent heat are exchanged between the outside air OA and the return air RA as the outside air OA passes through the total heat exchanger 24. The return air RA that has passed through the total heat exchanger 24 is discharged to the outside as exhaust air EA from the exhaust air outlet 212 through a duct.

[0028] 2, the outdoor air processing unit heat exchanger 25 is connected in series to the outdoor air unit expansion valve 26. The outdoor air unit expansion valve 26 is a solenoid valve that decompresses the refrigerant. The outdoor air processing unit heat exchanger 25 and the outdoor air unit expansion valve 26, which are connected in series, are connected to the outdoor unit 1 by a refrigerant flow path 5.

[0029] In the refrigerant circuit, the refrigerant flows from the outdoor unit 1 to the outdoor air processing unit 2, passes through the outdoor air processing unit heat exchanger 25 and the outdoor air unit expansion valve 26, and then returns to the outdoor unit 1. The operation of the multi-air conditioning system can be switched between cooling operation and heating operation. The direction in which the refrigerant flows in the outdoor air processing unit 2 switches depending on whether the multi-air conditioning system is switched between cooling operation and heating operation.

[0030] 3, the outdoor air processing unit heat exchanger 25 is disposed in the section of the supply air duct 215 between the total heat exchanger 24 and the supply air outlet 213. The outdoor air processing unit heat exchanger 25 exchanges heat between the refrigerant flowing through the outdoor air processing unit heat exchanger 25 and the outdoor air OA that has passed through the total heat exchanger 24. Therefore, the outdoor air processing unit heat exchanger 25 is a direct expansion coil that exchanges heat between the refrigerant and the outdoor air OA by a phase change of the refrigerant.

[0031] A thermal load is applied to the refrigerant flowing through the outdoor air processing unit heat exchanger 25 by heat exchange between the refrigerant and the outdoor air OA. The refrigerant to which a thermal load has been applied in the outdoor air processing unit heat exchanger 25 is sent to the outdoor unit 1. Therefore, the connection capacity of the outdoor air processing unit 2 to the outdoor unit 1 is the capacity of the outdoor air processing unit heat exchanger 25. In this embodiment, the connection capacity of the outdoor air processing unit 2 is 7.1 kW.

[0032] The humidifier 27 is disposed in a section of the supply air duct 215 between the outdoor air processing unit heat exchanger 25 and the supply air outlet 213. The humidifier 27 is capable of humidifying the outdoor air OA that has passed through the outdoor air processing unit heat exchanger 25.

[0033] Humidifier 27 has a humidifying element 271 and a water supply device (not shown). Humidifying element 271 is arranged in air supply duct 251. A porous body capable of retaining water is used as humidifying element 271. The water supply device is arranged outside casing 21. Humidifying element 271 is connected to the water supply device via a water supply pipe 272. Water supply pipe 272 is provided with a water supply valve 273.

[0034] The water supply device is capable of supplying water to the humidification element 271 through a water supply pipe 272. The amount of water supplied from the water supply device to the humidification element 271 is adjusted by a water supply valve 273. The humidifier 27 is capable of humidifying the outside air OA by bringing the outside air OA that has passed through the outside air processing unit heat exchanger 25 into contact with the humidification element 271. The outside air OA that has passed through the humidifier 27 is supplied into the room as supply air SA from the supply air outlet 213 through a duct. The amount of humidification of the outside air OA and the temperature of the supply air SA are adjusted by the amount of heat exchange between the refrigerant flowing through the outside air processing unit heat exchanger 25 and the outside air OA.

[0035] An outdoor air temperature sensor 281 and an outdoor air humidity sensor 282 are arranged in the supply air duct 215. The outdoor air temperature sensor 281 detects the temperature of the outdoor air OA, which is air drawn in from outside the room by the outdoor air processing unit 2, as the outdoor air detected temperature. The outdoor air humidity sensor 282 detects the relative humidity of the outdoor air OA, which is air drawn in from outside the room by the outdoor air processing unit 2, as the outdoor air detected humidity.

[0036] The outdoor air temperature sensor 281 and outdoor air humidity sensor 282 are disposed in a section of the supply air duct 215 between the outdoor air inlet 211 and the total heat exchanger 24. The outdoor air temperature sensor 281 detects the temperature of the outdoor air OA before passing through the total heat exchanger 24, the outdoor air processing unit heat exchanger 25, and the humidifier 27 in the outdoor air processing unit 2 as the detected outdoor air temperature. The outdoor air humidity sensor 282 detects the relative humidity of the outdoor air OA before passing through the total heat exchanger 24, the outdoor air processing unit heat exchanger 25, and the humidifier 27 in the outdoor air processing unit 2 as the detected outdoor air humidity.

[0037] An indoor air temperature sensor 283 and an indoor air humidity sensor 284 are arranged in the exhaust air duct 216. The indoor air temperature sensor 283 detects, as the indoor air detected temperature, the temperature of the return air RA, which is the air sucked in from the room by the outdoor air processing unit 2. The indoor air humidity sensor 284 detects, as the indoor air detected humidity, the relative humidity of the return air RA, which is the air sucked in from the room by the outdoor air processing unit 2.

[0038] The indoor air temperature sensor 283 and the indoor air humidity sensor 284 are disposed in a section of the exhaust air duct 216 between the indoor air inlet 214 and the total heat exchanger 24. The indoor air temperature sensor 283 detects the temperature of the air before it passes through the total heat exchanger 24 in the outdoor air processing unit 2, i.e., the temperature of the return air RA, as the indoor air detected temperature. The indoor air humidity sensor 284 detects the relative humidity of the air before it passes through the total heat exchanger 24 in the outdoor air processing unit 2, i.e., the return air RA, as the indoor air detected humidity.

[0039] The outdoor air unit control unit 28 controls the intake air blower 22, the exhaust air blower 23, the outdoor air unit expansion valve 26, and the switching damper 217. The outdoor air unit control unit 28 adjusts the heat exchange capacity of the outdoor air processing unit heat exchanger 25 based on the detection results of the outdoor air temperature sensor 281 and the outdoor air humidity sensor 282. A target temperature of the indoor air is set as the indoor target temperature, and a target humidity of the indoor air is set as the indoor target humidity in the outdoor air unit control unit 28 by operating the outdoor air processing remote control 20. The outdoor air unit control unit 28 adjusts the heat exchange capacity of the outdoor air processing unit heat exchanger 25 by comparing the indoor target temperature and the indoor target humidity with the indoor air detected temperature and the indoor air detected humidity, which are the detection results of the outdoor air temperature sensor 281 and the outdoor air humidity sensor 282, respectively. The outdoor air unit control unit 28 adjusts the heat exchange capacity of the outdoor air processing unit heat exchanger 25 by adjusting the opening degree of the outdoor air unit expansion valve 26.

[0040] As shown in FIG. 2, each indoor unit 3 has an indoor unit heat exchanger 31, an indoor unit expansion valve 32, an indoor unit blower 33, and an indoor unit control unit (not shown).

[0041] The indoor unit heat exchanger 31 is connected in series to the indoor unit expansion valve 32. The indoor unit expansion valve 32 is a solenoid valve that decompresses the refrigerant. The indoor unit heat exchanger 31 and the indoor unit expansion valve 32, which are connected in series to each other, are connected to the outdoor unit 1 by a refrigerant flow path 5.

[0042] In the refrigerant circuit, the refrigerant flows from the outdoor unit 1 to the indoor unit 3, passes through the indoor unit heat exchanger 31 and the indoor unit expansion valve 32, and then returns to the outdoor unit 1. The direction in which the refrigerant flows in the indoor unit 3 switches depending on whether the multi-air conditioning system is in cooling operation or heating operation.

[0043] The indoor unit blower 33 generates a flow of air that passes through the indoor unit heat exchanger 31. In each indoor unit 3, operation of the indoor unit blower 33 causes indoor air drawn into the indoor unit 3 from the room to pass through the indoor unit heat exchanger 31, and the air that has passed through the indoor unit heat exchanger 31 is supplied from the indoor unit 3 to the room. The indoor unit heat exchanger 31 exchanges heat between the refrigerant flowing through the indoor unit heat exchanger 31 and the air drawn into the indoor unit 3 from the room. In this way, the temperature of the indoor air is adjusted in each indoor unit 3.

[0044] A thermal load is applied to the refrigerant flowing through the indoor unit heat exchanger 31 by heat exchange between the refrigerant and the indoor air. The refrigerant that has been given a thermal load in the indoor unit heat exchanger 31 is sent to the outdoor unit 1. Therefore, the connection capacity of each indoor unit 3 to the outdoor unit 1 is the capacity of the indoor unit heat exchanger 31 in each indoor unit 3. In this embodiment, the connection capacity of each indoor unit 3 is 7.1 kW.

[0045] The indoor unit control unit controls the indoor unit expansion valve 32 and the indoor unit blower 33. The indoor unit control unit also adjusts the heat exchange capacity of the indoor unit heat exchanger 31 based on the detection result of the indoor air temperature sensor 283, i.e., the detected indoor air temperature. An indoor target temperature can be set in each indoor unit 3 by command from the indoor unit remote control 30. In each indoor unit 3, the indoor unit control unit adjusts the heat exchange capacity of the indoor unit heat exchanger 31 by comparing the indoor target temperature set in each indoor unit 3 by operation of the indoor unit remote control 30 with the detected indoor air temperature. The heat exchange capacity of the indoor unit heat exchanger 31 is adjusted by the indoor unit control unit adjusting the opening of the indoor unit expansion valve 32.

[0046] The outdoor unit 1 has a compressor 11, an outdoor unit heat exchanger 12, a four-way valve 13, an outdoor unit blower 14, and an outdoor unit control unit (not shown). The outdoor unit control unit controls the compressor 11, the four-way valve 13, and the outdoor unit blower 14.

[0047] The refrigerant flow path 5, which is connected to the outdoor air processing unit 2 and each indoor unit 3, is connected to an outdoor unit heat exchanger 12 and a four-way valve 13 in the outdoor unit 1. In the outdoor unit 1, the compressor 11 and the outdoor unit heat exchanger 12 are connected to the four-way valve 13.

[0048] The four-way valve 13 is a solenoid valve that switches the refrigerant flow path in response to switching between cooling operation and heating operation of the multi-air conditioning system. During cooling operation, the four-way valve 13 guides the refrigerant from the compressor 11 to the outdoor unit heat exchanger 12, and guides the refrigerant from each of the outdoor air processing unit 2 and each of the indoor units 3 to the compressor 11. During heating operation, the four-way valve 13 guides the refrigerant from the compressor 11 to the outdoor air processing unit 2 and each of the indoor units 3, and guides the refrigerant from the outdoor unit heat exchanger 12 to the compressor 11. In Figure 2, the refrigerant flow path in the four-way valve 13 during cooling operation is shown by a solid line, and the refrigerant flow path in the four-way valve 13 during heating operation is shown by a dashed line.

[0049] The compressor 11 compresses the refrigerant. The output of the compressor 11 can be changed by changing the operating frequency of the compressor 11. The outdoor unit blower 14 generates a flow of outdoor air that passes through the outdoor unit heat exchanger 12. The outdoor unit heat exchanger 12 exchanges heat between the refrigerant and the outdoor air that passes through the outdoor unit heat exchanger 12 due to the operation of the outdoor unit blower 14.

[0050] During cooling operation of the multi-air conditioning system, the refrigerant compressed by the compressor 11 is sent to the outdoor unit heat exchanger 12. In the outdoor unit heat exchanger 12, the refrigerant releases heat to the outdoor air and is condensed. The refrigerant is then sent to the outdoor air processing unit 2 and each of the indoor units 3.

[0051] The refrigerant sent to the outdoor air processing unit 2 is decompressed by the outdoor air unit expansion valve 26, and then sent to the outdoor air processing unit heat exchanger 25. Thereafter, the refrigerant absorbs heat from the outdoor air OA in the outdoor air processing unit heat exchanger 25 and evaporates. As a result, in the outdoor air processing unit 2, a heat load is applied to the refrigerant flowing through the outdoor air processing unit heat exchanger 25. Thereafter, the refrigerant returns to the compressor 11 of the outdoor unit 1.

[0052] The refrigerant sent to each indoor unit 3 is decompressed by the indoor unit expansion valve 32 and then sent to the indoor unit heat exchanger 31. After this, the refrigerant absorbs heat from the indoor air in the indoor unit heat exchanger 31 and evaporates. As a result, in each indoor unit 3, a heat load is applied to the refrigerant flowing through the indoor unit heat exchanger 31. After this, the refrigerant returns to the compressor 11 of the outdoor unit 1.

[0053] The heat load applied to the refrigerant in each of the outdoor air processing unit 2 and each of the indoor units 3 is processed in the outdoor unit 1 by the outdoor unit heat exchanger 12 releasing heat from the refrigerant to the outdoor air.

[0054] During cooling operation in the outdoor air processing unit 2, outdoor air OA is sucked into the inside of the casing 21 from the outdoor air intake 211, cooled by passing through the total heat exchanger 24 and the outdoor air processing unit heat exchanger 25, and then passes through the humidifier 27 to be supplied into the room as supply air SA.

[0055] On the other hand, during heating operation of the multi-air conditioning system, the refrigerant compressed by the compressor 11 is sent to the outdoor air processing unit 2 and each of the indoor units 3.

[0056] The refrigerant sent to the outdoor air processing unit 2 is condensed by releasing heat to the outdoor air OA in the outdoor air processing unit heat exchanger 25. As a result, in the outdoor air processing unit 2, a heat load is applied to the refrigerant flowing through the outdoor air processing unit heat exchanger 25. Thereafter, the refrigerant is sent to the outdoor air unit expansion valve 26, where it is decompressed, and then sent to the outdoor unit heat exchanger 12 of the outdoor unit 1.

[0057] The refrigerant sent to each indoor unit 3 is condensed by releasing heat to the indoor air in the indoor unit heat exchanger 31. As a result, in each indoor unit 3, a heat load is applied to the refrigerant flowing through the indoor unit heat exchanger 31. The refrigerant is then sent to the indoor unit expansion valve 32, where it is decompressed, and then sent to the outdoor unit heat exchanger 12 of the outdoor unit 1.

[0058] The refrigerant sent from the outdoor air processing unit 2 and each indoor unit 3 to the outdoor unit heat exchanger 12 absorbs heat from the outdoor air in the outdoor unit heat exchanger 12 and evaporates, and then returns to the compressor 11. The thermal load applied to the refrigerant in the outdoor air processing unit 2 and each indoor unit 3 is handled in the outdoor unit 1 by the outdoor unit heat exchanger 12 absorbing heat from the outdoor air into the refrigerant.

[0059] During heating operation, in the outdoor air processing unit 2, outdoor air OA is drawn into the inside of the casing 21 through the outdoor air intake 211, heated by passing through the total heat exchanger 24 and the outdoor air processing unit heat exchanger 25, and then humidified in the humidifier 27 and supplied into the room as supply air SA.

[0060] Here, the total connection capacity of the three indoor units 3 to the outdoor unit 1 is taken as the indoor unit total connection capacity B [kW], and the total connection capacity of the outdoor air processing units 2 to the outdoor unit 1 is taken as the outdoor air unit total connection capacity C [kW]. In this case, in a multi-air conditioning system, the sum of the indoor unit total connection capacity B and the outdoor air unit total connection capacity C exceeds the heat treatment capacity A [kW] of the outdoor unit 1. The heat treatment capacity A of the outdoor unit 1 is the capacity of the outdoor unit 1 to process the heat load applied to the refrigerant in the outdoor air processing unit 2 and each indoor unit 3. In this embodiment, the heat treatment capacity A of the outdoor unit 1 is taken as 22.4 [kW]. Therefore, in this embodiment, the sum of the indoor unit total connection capacity B and the outdoor air unit total connection capacity C is 7.1 [kW] x 4 units = 28.4 [kW], which exceeds the heat treatment capacity A of the outdoor unit 1.

[0061] The monitoring device 4 monitors indoor operation information that changes in accordance with changes in the heat load during operation of each indoor unit 3. The opening of each indoor unit expansion valve 32 changes in accordance with the heat load during operation of each indoor unit 3. Therefore, in this embodiment, information related to the opening of each indoor unit expansion valve 32 is used as the indoor operation information monitored by the monitoring device 4. That is, in this embodiment, information related to the opening of the indoor unit expansion valve 32 in each indoor unit 3 is monitored by the monitoring device 4. Information related to the opening of each indoor unit expansion valve 32 is taken into the monitoring device 4 from the indoor unit control unit of each indoor unit 3.

[0062] The monitoring device 4 determines whether or not it is necessary to restrict the operation of the multi-air conditioning system based on the indoor operation information, that is, information relating to the opening degree of each indoor unit expansion valve 32.

[0063] Specifically, the monitoring device 4 calculates the total heat load of each indoor unit 3 during operation as the indoor unit total load D [kW] based on information related to the opening degree of each indoor unit expansion valve 32, and specifies the required operating capacity by adding the total indoor unit load D to the total outdoor air unit connection capacity C. By comparing the required operating capacity with the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 determines whether or not it is necessary to restrict the operation of the multi-air conditioning system.

[0064] The monitoring device 4 makes a restriction determination that operation restriction is necessary when the required operation capacity exceeds the heat treatment capacity A of the outdoor unit 1. Furthermore, when the required operation capacity is equal to or less than the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 makes a non-restriction determination that operation restriction is unnecessary.

[0065] When the monitoring device 4 makes a restriction determination, it forcibly puts the outside air processing unit 2 into the thermo-off state via the outside air unit control unit 28. When the outside air processing unit 2 enters the thermo-off state, the outside air unit expansion valve 26 closes and stops the supply of refrigerant to the outside air processing unit heat exchanger 25. As a result, when the outside air processing unit 2 is in the thermo-off state, heat exchange between the outside air OA and the refrigerant does not occur in the outside air processing unit heat exchanger 25.

[0066] In this embodiment, even when the monitoring device 4 forcibly switches the state of the outdoor air processing unit 2 to the thermo-off state, the operation of the intake air blower 22 and the exhaust air blower 23 continues, and total heat exchange between the outdoor air OA and the return air RA is carried out in the total heat exchanger 24.

[0067] Next, the processing operation of the monitoring device 4 will be described. Here, the processing operation of the monitoring device 4 when the multi-air conditioning system is in heating operation will be described. Fig. 4 is a flowchart showing the processing operation of the monitoring device 4 of Fig. 1. The heat treatment capacity A of the outdoor unit 1, the total connected capacity B of the indoor units, and the total connected capacity C of the outdoor air units are inputted into the monitoring device 4 in advance.

[0068] When the multi-air conditioning system is operating, the monitoring device 4 determines in step S1 whether the sum of the total connected capacity B of the indoor units and the total connected capacity C of the outdoor air units is equal to or less than the heat treatment capacity A of the outdoor unit 1. If the sum of the total connected capacity B of the indoor units and the total connected capacity C of the outdoor air units is equal to or less than the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S2. In step S2, the monitoring device 4 sets the operation of the multi-air conditioning system to normal operation.

[0069] If the sum of the total indoor unit connection capacity B and the total outdoor air unit connection capacity C exceeds the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S3. In step S3, the monitoring device 4 determines whether the sum of the total indoor unit load D and the total outdoor air unit connection capacity C is equal to or less than the heat treatment capacity A of the outdoor unit 1. The total indoor unit load D is the sum of the heat loads of each indoor unit 3 during operation. In step S3, the monitoring device 4 calculates the total indoor unit load D based on information related to the opening degree of each indoor unit expansion valve 32 during operation. Based on this, the monitoring device 4 determines whether or not it is necessary to restrict the operation of the multi-air conditioning system.

[0070] If, in step S3, the sum of the indoor unit total load D and the outdoor air unit total connection capacity C is equal to or less than the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 makes a non-restriction determination that operation restriction is unnecessary, and proceeds to step S2. As a result, operation of the multi-air conditioning system is set to normal operation.

[0071] If in step S3 the sum of the indoor unit total load amount D and the outdoor air unit total connection capacity C exceeds the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 makes a restriction determination that operation restriction is necessary, and proceeds to step S4. In step S4, the monitoring device 4 forcibly sets the state of the outdoor air processing unit 2 to the thermo-off state. This closes the outdoor air unit expansion valve 26, and stops the supply of refrigerant to the outdoor air processing unit heat exchanger 25. After this, the monitoring device 4 proceeds to step S5.

[0072] In step S5, the monitoring device 4 calculates the indoor unit total load D, and again determines whether the sum of the indoor unit total load D and the outdoor air unit total connection capacity C is equal to or less than the heat treatment capacity A of the outdoor unit 1. If the sum of the indoor unit total load D and the outdoor air unit total connection capacity C exceeds the heat treatment capacity A of the outdoor unit 1 in step S5, the monitoring device 4 keeps the outdoor air processing unit 2 in the thermo-off state and repeats the determination in step S5 until the sum of the indoor unit total load D and the outdoor air unit total connection capacity C becomes equal to or less than the heat treatment capacity A of the outdoor unit 1.

[0073] In step S5, when the sum of the indoor unit total load D and the outdoor air unit total connection capacity C becomes equal to or less than the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S2 and returns the operation of the multi-air conditioning system to normal operation.

[0074] The processing operation of the monitoring device 4 when the multi-air conditioning system is in cooling operation is the same as the above-mentioned processing operation of the monitoring device 4 when the multi-air conditioning system is in heating operation. Furthermore, the above-mentioned processing operation of the monitoring device 4 may be performed continuously while the multi-air conditioning system is in operation, or may be performed at regular intervals.

[0075] In such a multi-air conditioning system, the monitoring device 4 determines whether operation needs to be restricted based on indoor operation information that changes in accordance with changes in the heat load during operation in each indoor unit 3. When the monitoring device 4 determines that operation needs to be restricted, it forcibly switches the outdoor air processing unit 2 to the thermo-off state. This makes it possible to suppress the heat load during operation in the outdoor air processing unit 2, and prevent the outdoor unit 1 from becoming overloaded. This eliminates the need to limit the connection capacity of the outdoor air processing unit 2 to the outdoor unit 1. Therefore, it is possible to relax the limit on the total connection capacity of the outdoor air processing unit 2 and the indoor units 3 to the outdoor unit 1.

[0076] Furthermore, the monitoring device 4 determines the total indoor unit load D, which is the sum of the heat loads during operation of each indoor unit 3, based on information related to the opening degree of the indoor unit expansion valves 32 in each indoor unit 3. The monitoring device 4 determines the required operating capacity by adding the total indoor unit load D to the total outdoor air unit connection capacity C. The monitoring device 4 makes a restriction determination when the required operating capacity exceeds the heat treatment capacity A of the outdoor unit 1. This makes it possible to easily grasp the indoor unit total load D with a simple configuration. This makes it possible to easily relax restrictions on the total connection capacity of the outdoor air treatment units 2 and indoor units 3 relative to the outdoor unit 1 with a simple configuration.

[0077] Embodiment 2 In the first embodiment, information relating to the opening degree of the indoor unit expansion valve 32 in each indoor unit 3 is used as the indoor operation information. However, information on the indoor temperature difference, which is the difference between the indoor target temperature set in each indoor unit 3 and the indoor air detected temperature, which is the detection result of the indoor air temperature sensor 283, may also be used as the indoor operation information.

[0078] The configuration of this embodiment is the same as that of Embodiment 1 except for the monitoring device 4. In this embodiment, information about the indoor target temperature E [°C] set in each indoor unit 3 by operating the indoor unit remote control 30 is sent from the indoor unit control unit to the monitoring device 4. Also in this embodiment, information about the detected indoor air temperature F [°C], which is the detection result of the indoor air temperature sensor 283, is sent from the outdoor air unit control unit 28 to the monitoring device 4. The monitoring device 4 calculates the difference between the indoor target temperature E and the detected indoor air temperature F as the indoor temperature difference, and determines whether or not it is necessary to restrict the operation of the multi-air conditioning system based on the information about the indoor temperature difference. The indoor temperature difference changes according to changes in the heat load of each indoor unit 3 during operation. In this embodiment, the value obtained by subtracting the detected indoor air temperature F from the indoor target temperature E is taken as the indoor temperature difference.

[0079] Specifically, the monitoring device 4 compares the indoor temperature difference with a preset temperature difference threshold to determine whether or not it is necessary to restrict the operation of the multi-air conditioning system. Therefore, in this embodiment, information on the indoor temperature difference is used as indoor operation information. The temperature difference threshold is a positive value during cooling operation and a negative value during heating operation. In this embodiment, the temperature difference threshold is set to +5°C during cooling operation and -5°C during heating operation. The absolute value of the temperature difference threshold is not limited to 5, and the absolute value of the temperature difference threshold may be changeable.

[0080] When the indoor temperature difference exceeds the temperature difference threshold, the monitoring device 4 makes a restriction determination that operation restriction is necessary. Also, when the indoor temperature difference is equal to or less than the temperature difference threshold, the monitoring device 4 makes a non-restriction determination that operation restriction is unnecessary. Other configurations are the same as those in the first embodiment.

[0081] Next, the processing operation of the monitoring device 4 will be described. In this embodiment, the processing operation of the monitoring device 4 when the multi-air conditioning system is in cooling operation will be described. Fig. 5 is a flowchart showing the processing operation of the monitoring device 4 according to embodiment 2. As in embodiment 1, the heat treatment capacity A of the outdoor unit 1, the total connected capacity B of the indoor units, and the total connected capacity C of the outdoor air units are input in advance to the monitoring device 4.

[0082] When the multi-air conditioning system is operating, the monitoring device 4, as in embodiment 1, determines in step S1 whether the sum of the total connected capacity B of the indoor units and the total connected capacity C of the outdoor air units is equal to or less than the heat treatment capacity A of the outdoor unit 1. If the sum of the total connected capacity B of the indoor units and the total connected capacity C of the outdoor air units is equal to or less than the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S2. In step S2, the monitoring device 4 sets the operation of the multi-air conditioning system to normal operation.

[0083] If the sum of the total connected capacity B of the indoor units and the total connected capacity C of the outdoor air units exceeds the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S11. In step S11, the monitoring device 4 determines whether the indoor temperature difference, which is the difference between the indoor target temperature E and the indoor air detected temperature F, exceeds +5°C, which is set as the temperature difference threshold. Based on this, the monitoring device 4 determines whether it is necessary to restrict the operation of the multi-air conditioning system.

[0084] If the indoor temperature difference is equal to or less than the temperature difference threshold in step S11, the monitoring device 4 makes a non-restriction determination that operation restriction is unnecessary, and proceeds to step S2, whereby the operation of the multi-air conditioning system is set to normal operation.

[0085] If the indoor temperature difference exceeds the temperature difference threshold in step S11, the monitoring device 4 makes a restriction determination that operation restriction is necessary, and proceeds to step S12. In step S12, the monitoring device 4 sets the state of the outdoor air processing unit 2 to the thermo-off state. This closes the outdoor air unit expansion valve 26, and stops the supply of refrigerant to the outdoor air processing unit heat exchanger 25. Thereafter, the monitoring device 4 proceeds to step S13.

[0086] In step S13, the monitoring device 4 again determines whether the indoor temperature difference, which is the difference between the indoor target temperature E and the indoor air detected temperature F, exceeds the temperature difference threshold. If the indoor temperature difference is equal to or less than the temperature difference threshold in step S13, the monitoring device 4 keeps the outdoor air processing unit 2 in the thermo-off state and repeats the determination in step S13 until the indoor temperature difference exceeds the temperature difference threshold.

[0087] If the indoor temperature difference exceeds the temperature difference threshold in step S13, the monitoring device 4 advances the process to step S2 and switches the operation of the multi-air conditioning system to normal operation.

[0088] The above processing operation of the monitoring device 4 may be performed constantly while the multi-air conditioning system is in operation, or may be performed at regular intervals.

[0089] In such a multi-air conditioning system, information on the indoor temperature difference, which is the difference between the indoor target temperature E set in the indoor unit 3 and the indoor air detected temperature F detected by the indoor air temperature sensor 283, is used as indoor operation information. The monitoring device 4 performs a restriction determination when the indoor temperature difference exceeds the temperature difference threshold. Even in this way, it is possible to easily grasp changes in the heat load amount during operation in the indoor unit 3 with a simple configuration, and it is possible to prevent the outdoor unit 1 from becoming overloaded. This makes it possible to easily relax restrictions on the total connection capacity of the outdoor air processing unit 2 and the indoor units 3 to the outdoor unit 1 with a simple configuration.

[0090] Embodiment 3 In the first and second embodiments, when the monitoring device 4 makes a restriction determination that operation restriction is necessary, it forcibly puts the outdoor air processing unit 2 into the thermo-off state. However, when the monitoring device 4 makes a restriction determination, it may be possible to select either indoor unit restriction control, which forcibly puts each indoor unit 3 into the thermo-off state, or outdoor air unit restriction control, which forcibly puts the outdoor air processing unit 2 into the thermo-off state.

[0091] That is, in the first and second embodiments, by setting the outdoor air processing unit 2 to the thermo-off state, priority is given to the processing of the sensible heat load by operating each indoor unit 3 over the processing of the latent heat load by operating the outdoor air processing unit 2. On the other hand, depending on the temperature and humidity of the air indoors or outdoors, there may be cases where energy savings in the operation of the multi-air conditioning system are improved by prioritizing the processing of the latent heat load by operating the outdoor air processing unit 2 over the processing of the sensible heat load by operating each indoor unit 3.

[0092] In this embodiment, when the monitoring device 4 makes a restriction determination, it is able to select either indoor unit restriction control, which forcibly switches each indoor unit 3 to the thermo-off state, or outdoor air unit restriction control, which forcibly switches the outdoor air processing unit 2 to the thermo-off state. Furthermore, when the monitoring device 4 makes a restriction determination, it determines whether or not to prioritize the selection of indoor unit restriction control over the selection of outdoor air unit restriction control based on the detection results of the indoor air temperature sensor 283 and the indoor air humidity sensor 284, i.e., the detected indoor air temperature and detected indoor air humidity.

[0093] Specifically, when the monitoring device 4 makes a restriction determination, it calculates the indoor detected absolute humidity H [g / kgDA], which is the absolute humidity of the indoor air, based on the indoor air detected temperature and indoor air detected humidity. Based on the calculated indoor detected absolute humidity H, the monitoring device 4 determines whether to prioritize selection of indoor unit restriction control over selection of outdoor air unit restriction control. That is, when the monitoring device 4 makes a restriction determination, it compares the indoor detected absolute humidity H with the indoor target absolute humidity G [g / kgDA] to determine whether to prioritize selection of indoor unit restriction control over selection of outdoor air unit restriction control.

[0094] Here, the outdoor air processing unit 2 dehumidifies the outdoor air OA during cooling operation and humidifies the outdoor air OA during heating operation. Therefore, during cooling operation, if the indoor detected absolute humidity H is equal to or lower than the indoor target absolute humidity G [g / kgDA], the latent heat load on the indoor air has already been treated, and so there is less need to dehumidify by operating the outdoor air processing unit 2. On the other hand, during heating operation, if the indoor detected absolute humidity H is equal to or lower than the indoor target absolute humidity G, there is more need to humidify by operating the outdoor air processing unit 2. For this reason, the determination criterion based on comparing the indoor detected absolute humidity H and the indoor target absolute humidity G is reversed between cooling operation and heating operation.

[0095] Therefore, when the indoor detected absolute humidity H during cooling operation exceeds the indoor target absolute humidity G, the monitoring device 4 prioritizes the selection of indoor unit limiting control over the selection of outdoor air unit limiting control. Furthermore, when the indoor detected absolute humidity H during cooling operation is equal to or lower than the indoor target absolute humidity G, the monitoring device 4 does not select the indoor unit limiting control and determines whether or not to select the outdoor air unit limiting control. On the other hand, when the indoor detected absolute humidity H during heating operation is lower than the indoor target absolute humidity G, the monitoring device 4 prioritizes the selection of indoor unit limiting control over the selection of outdoor air unit limiting control. Furthermore, when the indoor detected absolute humidity H during heating operation is equal to or higher than the indoor target absolute humidity G, the monitoring device 4 does not select the indoor unit limiting control and determines whether or not to select the outdoor air unit limiting control. The determination of whether or not to select the outdoor air unit limiting control is made by comparing the sum of the indoor unit total load D and the outdoor air unit total connected capacity C [kW] with the heat treatment capacity A of the outdoor unit 1.

[0096] The indoor target absolute humidity G may be set in advance in the monitoring device 4, or may be set in the outdoor air unit control section 28 by operating the outdoor air processing remote control 20. Other configurations are the same as those in the first embodiment.

[0097] Next, the processing operation of the monitoring device 4 will be described. In this embodiment, the processing operation of the monitoring device 4 when the multi-air conditioning system is in cooling operation will be described. Fig. 6 is a flowchart showing the processing operation of the monitoring device 4 according to embodiment 3. As in embodiment 1, the heat treatment capacity A of the outdoor unit 1, the total connected capacity B of the indoor units, and the total connected capacity C of the outdoor air units are input in advance to the monitoring device 4.

[0098] When the multi-air conditioning system is operating, the monitoring device 4, as in embodiment 1, determines in step S1 whether the sum of the total connected capacity B of the indoor units and the total connected capacity C of the outdoor air units is equal to or less than the heat treatment capacity A of the outdoor unit 1. If the sum of the total connected capacity B of the indoor units and the total connected capacity C of the outdoor air units is equal to or less than the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S2. In step S2, the monitoring device 4 sets the operation of the multi-air conditioning system to normal operation.

[0099] If the sum of the total connected capacity B of the indoor units and the total connected capacity C of the outdoor air units exceeds the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S3. In step S3, the monitoring device 4 determines whether the sum of the total load D of the indoor units and the total connected capacity C of the outdoor air units is equal to or less than the heat treatment capacity A of the outdoor unit 1, as in the first embodiment.

[0100] If the sum of the indoor unit total load D and the outdoor air unit total connection capacity C is equal to or less than the heat treatment capacity A of the outdoor unit 1 in step S3, the monitoring device 4 makes a non-restriction determination and proceeds to step S2, whereby the operation of the multi-air conditioning system is set to normal operation.

[0101] If the sum of the indoor unit total load D and the outdoor air unit total connection capacity C exceeds the heat treatment capacity A of the outdoor unit 1 in step S3, the monitoring device 4 performs a restriction determination and proceeds to step S21. In step S21, the monitoring device 4 determines whether the indoor detected absolute humidity H is equal to or lower than the indoor target absolute humidity G. In step S21, the monitoring device 4 calculates the indoor detected absolute humidity H based on the indoor air detected temperature and the indoor air detected humidity. As a result, the monitoring device 4 determines whether to prioritize selection of indoor unit restriction control over selection of outdoor air unit restriction control.

[0102] If the indoor detected absolute humidity H exceeds the indoor target absolute humidity G in step S21, the monitoring device 4 selects indoor unit restriction control and forcibly switches each indoor unit 3 to the thermo-off state. This closes the indoor unit expansion valves 32 and stops the supply of refrigerant to the indoor unit heat exchangers 31. After this, the monitoring device 4 proceeds to step S23.

[0103] In step S23, the monitoring device 4 calculates the indoor detected absolute humidity H and again determines whether the indoor detected absolute humidity H is equal to or less than the indoor target absolute humidity G. If the indoor detected absolute humidity H exceeds the indoor target absolute humidity G in step S23, the monitoring device 4 repeats the determination in step S23 while keeping each indoor unit 3 in the thermo-off state until the indoor detected absolute humidity H becomes equal to or less than the indoor target absolute humidity G.

[0104] If the indoor detected absolute humidity H is equal to or lower than the indoor target absolute humidity G in step S23, the monitoring device 4 proceeds to step S24. Also, if the indoor detected absolute humidity H is equal to or lower than the indoor target absolute humidity G in step S21, the monitoring device 4 proceeds to step S24.

[0105] In step S24, the monitoring device 4 calculates the indoor unit total load D, and again determines whether the sum of the indoor unit total load D and the outdoor air unit total connection capacity C is less than or equal to the heat treatment capacity A of the outdoor unit 1. This causes the monitoring device 4 to determine whether or not it is necessary to select outdoor air unit limiting control. If in step S24 the sum of the indoor unit total load D and the outdoor air unit total connection capacity C is less than or equal to the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S2 without selecting outdoor air unit limiting control, and the multi-air conditioning system operates normally.

[0106] If the sum of the indoor unit total load amount D and the outdoor air unit total connection capacity C exceeds the heat treatment capacity A of the outdoor unit 1 in step S24, the monitoring device 4 selects outdoor air unit restriction control and proceeds to step S25, forcibly switching the outdoor air processing unit 2 to the thermo-off state. This closes the outdoor air unit expansion valve 26, and stops the supply of refrigerant to the outdoor air processing unit heat exchanger 25. After this, the monitoring device 4 proceeds to step S26.

[0107] In step S26, the monitoring device 4 calculates the indoor unit total load D, and again determines whether the sum of the indoor unit total load D and the outdoor air unit total connection capacity C is equal to or less than the heat treatment capacity A of the outdoor unit 1. If the sum of the indoor unit total load D and the outdoor air unit total connection capacity C exceeds the heat treatment capacity A of the outdoor unit 1 in step S26, the monitoring device 4 keeps the outdoor air processing unit 2 in the thermo-off state and repeats the determination in step S26 until the sum of the indoor unit total load D and the outdoor air unit total connection capacity C becomes equal to or less than the heat treatment capacity A of the outdoor unit 1.

[0108] In step S26, when the sum of the indoor unit total load D and the outdoor air unit total connection capacity C becomes equal to or less than the heat treatment capacity A of the outdoor unit 1, the monitoring device 4 proceeds to step S2 and returns the operation of the multi-air conditioning system to normal operation.

[0109] The processing operation of the monitoring device 4 during heating operation of the multi-air conditioning system is the same as the above-mentioned processing operation of the monitoring device 4 during cooling operation of the multi-air conditioning system, except that the judgment criteria in steps S21 and S23, which are based on comparison between the indoor detected absolute humidity H and the indoor target absolute humidity G, are reversed from those during cooling operation. Furthermore, the above-mentioned processing operation of the monitoring device 4 may be performed continuously while the multi-air conditioning system is in operation, or may be performed at regular intervals.

[0110] In such a multi-air conditioning system, when the monitoring device 4 makes a restriction determination, it is possible to select either indoor unit restriction control or outdoor air unit restriction control. This makes it possible to prevent the outdoor unit 1 from becoming overloaded. This makes it possible to relax the restriction on the total connection capacity of the outdoor air processing unit 2 and the indoor units 3 to the outdoor unit 1. It is also possible to prioritize indoor comfort by processing the sensible heat load through operation of each indoor unit 3, or to prioritize energy conservation by processing the latent heat load through operation of the outdoor air processing unit 2. This increases the degree of freedom in the method for limiting the heat load amount processed by the outdoor unit 1.

[0111] Furthermore, when the monitoring device 4 makes a restriction determination, it selects indoor unit restriction control if the indoor detected absolute humidity H during cooling operation exceeds the indoor target absolute humidity G, or if the indoor detected absolute humidity H during heating operation is lower than the indoor target absolute humidity G. Therefore, by prioritizing the processing of the latent heat load by operating the outdoor air processing unit 2, it is possible to more reliably achieve energy savings in the operation of the multi-air conditioning system.

[0112] In the third embodiment, the indoor detected absolute humidity H is calculated based on the detected indoor air temperature and the detected indoor humidity, and the indoor detected absolute humidity H is compared with the indoor target absolute humidity G to determine whether to prioritize indoor unit limiting control over outdoor air unit limiting control. The method for determining whether to prioritize indoor unit limiting control over outdoor air unit limiting control is not limited to this. When making a limiting determination, the monitoring device 4 may determine whether to prioritize indoor unit limiting control over outdoor air unit limiting control based on at least one of indoor temperature and humidity information and outdoor temperature and humidity information. The indoor temperature and humidity information is the detection results of the indoor air temperature sensor 283 and the indoor air humidity sensor 284, i.e., information on the detected indoor air temperature and humidity. The outdoor temperature and humidity information is the detection results of the outdoor air temperature sensor 281 and the outdoor air humidity sensor 282, i.e., information on the detected outdoor air temperature and humidity.

[0113] For example, outdoor air condition information may be set in the monitoring device 4, and the monitoring device 4 may compare the outdoor temperature and humidity information with the outdoor air condition information to determine whether to prioritize the selection of indoor unit limiting control over the selection of outdoor air unit limiting control. In this case, the outdoor air condition information is information indicating the relationship between the outdoor air temperature and the outdoor air relative humidity, which serves as a criterion for determining the selection between the indoor unit limiting control and the outdoor air unit limiting control.

[0114] Alternatively, for example, outdoor air condition information and indoor air condition information may be set in the monitoring device 4, and the monitoring device 4 may compare the difference between the outdoor air condition information and outdoor temperature and humidity information with the difference between the indoor air condition information and indoor temperature and humidity information to determine whether to prioritize indoor unit limiting control over outdoor air unit limiting control. In this case, the outdoor air condition information is information indicating the relationship between the outdoor air temperature and the outdoor air relative humidity, which serves as a criterion for selecting indoor unit limiting control and outdoor air unit limiting control. The indoor air condition information is information indicating the relationship between the indoor air temperature and the indoor air relative humidity, which serves as a criterion for selecting indoor unit limiting control and outdoor air unit limiting control.

[0115] Furthermore, in the third embodiment, when the monitoring device 4 makes a restriction determination, the monitoring device 4 may determine, based on seasonal information, whether to prioritize the selection of indoor unit restriction control over the selection of outdoor air unit restriction control. This allows the selection of indoor unit restriction control to be prioritized over the selection of outdoor air unit restriction control, for example, in winter when the air tends to be dry.

[0116] In addition, in each of the above-described embodiments, the number of indoor units 3 connected in parallel to the outdoor unit 1 together with the outdoor air processing units 2 is three. However, the number of indoor units 3 connected in parallel to the outdoor unit 1 together with the outdoor air processing units 2 may be one, two, four or more.

[0117] Furthermore, in each of the above embodiments, the number of outdoor air processing units 2 connected in parallel to the outdoor unit 1 together with the indoor units 3 is one. However, the number of outdoor air processing units 2 connected in parallel to the outdoor unit 1 together with the indoor units 3 may be two or more. In this case, the outdoor air temperature sensor 281, the outdoor air humidity sensor 282, the indoor air temperature sensor 283, and the indoor air humidity sensor 284 are provided in any of the two or more outdoor air processing units 2.

[0118] In addition, in Embodiments 1 and 3, information related to the opening degree of the indoor unit expansion valve 32 in each indoor unit 3 is used as the indoor operation information. In Embodiment 2, information on the indoor temperature difference, which is the difference between the indoor target temperature set in each indoor unit 3 and the detected indoor air temperature, is used as the indoor operation information. However, for example, information on the difference between the measured value during operation and the target value for the refrigerant superheat degree SH in each indoor unit 3, i.e., information on the indoor unit superheat degree difference, may also be used as the indoor operation information. Also, information on the difference between the measured value during operation and the target value for the refrigerant subcooling degree SC in each indoor unit 3, i.e., information on the indoor unit subcooling degree difference, may also be used as the indoor operation information. Furthermore, information on the difference between the measured value during operation and the target value for the operating frequency of the compressor 11 in the outdoor unit 1, i.e., information on the compressor frequency difference, may also be used as the indoor operation information. The indoor unit superheat degree difference, indoor unit subcooling degree difference, and compressor frequency difference all change according to changes in the heat load in each indoor unit 3 during operation. In these cases, when the indoor unit superheating degree difference, indoor unit subcooling degree difference, or compressor frequency difference is greater than the threshold value, the monitoring device 4 makes a restriction determination that operation restriction is necessary.

[0119] Furthermore, in each of the above-described embodiments, when the state of the outside air processing unit is forcibly set to the thermo-off state, the operation of each of the intake air blower 22 and the exhaust air blower 23 is maintained. However, when the state of the outside air processing unit is forcibly set to the thermo-off state, the monitoring device 4 may limit the operation of the intake air blower 22 and the exhaust air blower 23 to limit the amount of ventilation in the room.

[0120] If the outdoor air processing unit 2 continues to ventilate the room when the outdoor air processing unit is forcibly set to the thermo-off state, the amount of outdoor air supplied from the outdoors to the room is maintained. Therefore, there is a risk that the thermal load of the outdoor air supplied from the outdoors to the room will unnecessarily increase in the thermal load of each indoor unit 3. Therefore, when the monitoring device 4 makes a restriction determination, the outdoor air processing unit 2 is set to the thermo-off state and the operation of the intake air blower 22 and the exhaust air blower 23 is restricted, thereby suppressing an increase in the thermal load of each indoor unit 3. This more reliably prevents the outdoor unit 1 from entering an overload state. Therefore, the restriction on the total connection capacity of the outdoor air processing unit 2 and the indoor units 3 to the outdoor unit 1 can be more reliably relaxed.

[0121] When restricting the operation of the intake air blower 22 and the exhaust air blower 23, the monitoring device 4 reduces the output of the intake air blower 22 and the exhaust air blower 23 within a range that allows the required amount of ventilation in the room to be maintained. Furthermore, when restricting the operation of the intake air blower 22 and the exhaust air blower 23, the monitoring device 4 may stop the operation of the intake air blower 22 and the exhaust air blower 23 if it is within a set start-up time of the indoor unit 3 during which stopping of ventilation in the room is permitted.

[0122] In addition, in each of the above-described embodiments, the monitoring device 4 is provided separately from the outdoor unit 1. However, this is not limited to this, and the outdoor unit control unit included in the outdoor unit 1 may be configured as the monitoring device 4 by incorporating the functions of the monitoring device 4 into the outdoor unit control unit.

[0123] The configurations described in the above embodiments are merely examples of the contents of the present disclosure. The embodiments can be combined with other known technologies. Part of the configuration of the embodiments can be omitted or modified without departing from the gist of the present disclosure. [Explanation of symbols]

[0124] 1 outdoor unit, 2 outdoor air processing unit, 3 indoor unit, 4 monitoring device, 5 refrigerant flow path, 24 total heat exchanger, 25 outdoor air processing unit heat exchanger, 27 humidifier, 31 indoor unit heat exchanger, 32 indoor unit expansion valve, 281 outdoor air temperature sensor, 282 outdoor air humidity sensor, 283 indoor air temperature sensor, 284 indoor air humidity sensor, 22 intake air blower, 23 exhaust air blower.

Claims

1. The outdoor unit and one or more outside air processing units that supply outside air drawn in from outside the room as intake air into the room and discharge the air drawn in from the room to the outside as exhaust air; one or more indoor units that adjust the temperature of air drawn in from the room and supply the adjusted air to the room; Surveillance equipment and Equipped with the one or more outdoor air processing units and the one or more indoor units are connected in parallel to the outdoor unit by refrigerant flow paths through which a refrigerant flows, the one or more outdoor air processing units include a total heat exchanger, an outdoor air processing unit heat exchanger, and a humidifier; The total heat exchanger is capable of total heat exchange between the outside air drawn in from outside the room by the outside air processing unit and the air drawn in from inside the room by the outside air processing unit, the outside air processing unit heat exchanger is capable of exchanging heat between the refrigerant flowing through the outside air processing unit heat exchanger and the outside air that has passed through the total heat exchanger, The humidifier is capable of humidifying the outside air that has passed through the outside air processing unit heat exchanger, The one or more indoor units have an indoor unit heat exchanger, The indoor unit heat exchanger is capable of exchanging heat between the refrigerant flowing through the indoor unit heat exchanger and the air drawn in from the room by the indoor unit, the sum of the connection capacities of the one or more outdoor air processing units to the outdoor unit and the sum of the connection capacities of the one or more indoor units to the outdoor unit exceeds the heat treatment capacity of the outdoor unit, The monitoring device determines whether or not operation restriction is necessary based on indoor operation information that changes in accordance with changes in the heat load during operation of the one or more indoor units, and when it determines that operation restriction is necessary, it forcibly switches the state of the one or more outdoor air processing units to thermo-off state.

2. The one or more indoor units have an indoor unit expansion valve connected to the indoor unit heat exchanger, the indoor operation information is information regarding the opening degree of the indoor unit expansion valve in the one or more indoor units, The multi-air conditioning system of claim 1, wherein the monitoring device calculates the total heat load of the one or more indoor units during operation as the total indoor unit load based on information regarding the opening degree of the indoor unit expansion valve in the one or more indoor units, and determines the required operating capacity by adding the total indoor unit load to the total connection capacity of the one or more outdoor air processing units, and performs the restriction judgment when the required operating capacity exceeds the heat processing capacity of the outdoor unit.

3. any one of the one or more outside air processing units is provided with an indoor air temperature sensor that detects the temperature of the air drawn in from the room by the outside air processing unit as an indoor air detected temperature; The indoor operation information is information about an indoor temperature difference, which is the difference between an indoor target temperature set in the indoor unit as a target temperature of the indoor air and the indoor air detected temperature, The multi-air conditioning system according to claim 1 , wherein the monitoring device makes the restriction determination when the indoor temperature difference exceeds a temperature difference threshold.

4. The outdoor unit and one or more outside air processing units that supply outside air drawn in from outside the room as intake air into the room and discharge the air drawn in from the room to the outside as exhaust air; one or more indoor units that adjust the temperature of air drawn in from the room and supply the adjusted air to the room; Surveillance equipment and Equipped with the one or more outdoor air processing units and the one or more indoor units are connected in parallel to the outdoor unit by refrigerant flow paths through which a refrigerant flows, the one or more outdoor air processing units include a total heat exchanger, an outdoor air processing unit heat exchanger, and a humidifier; The total heat exchanger is capable of total heat exchange between the outside air drawn in from outside the room by the outside air processing unit and the air drawn in from inside the room by the outside air processing unit, the outside air processing unit heat exchanger is capable of exchanging heat between the refrigerant flowing through the outside air processing unit heat exchanger and the outside air that has passed through the total heat exchanger, The humidifier is capable of humidifying the outside air that has passed through the outside air processing unit heat exchanger, The one or more indoor units have an indoor unit heat exchanger, The indoor unit heat exchanger is capable of exchanging heat between the refrigerant flowing through the indoor unit heat exchanger and the air drawn in from the room by the indoor unit, the sum of the connection capacities of the one or more outdoor air processing units to the outdoor unit and the sum of the connection capacities of the one or more indoor units to the outdoor unit exceeds the heat treatment capacity of the outdoor unit, The monitoring device determines whether operation restriction is necessary based on indoor operation information that changes in accordance with changes in the heat load during operation in the one or more indoor units, and when it makes a restriction determination that operation restriction is necessary, it is possible to select either indoor unit restriction control that forcibly switches the state of the one or more indoor units to a thermo-off state, or outdoor air unit restriction control that forcibly switches the state of the one or more outdoor air processing units to a thermo-off state.This is a multi-air conditioning system.

5. any one of the one or more outdoor air processing units is provided with an indoor air temperature sensor that detects the temperature of the air drawn in by the outdoor air processing unit from the indoor space as an indoor air detected temperature, and an indoor air humidity sensor that detects the relative humidity of the air drawn in by the outdoor air processing unit from the indoor space as an indoor air detected humidity; The multi-air conditioning system of claim 4, wherein the monitoring device, when making the restriction determination, determines whether to prioritize the selection of the indoor unit restriction control over the selection of the outdoor air unit restriction control based on the detected indoor air temperature and the detected indoor air humidity.

6. Any one of the one or more outdoor air processing units is provided with an indoor air temperature sensor that detects the temperature of the air sucked by the outdoor air processing unit from the indoors as the indoor air detected temperature, an indoor air humidity sensor that detects the relative humidity of the air sucked by the outdoor air processing unit from the indoors as the indoor air detected humidity, an outdoor air temperature sensor that detects the temperature of the outdoor air sucked by the outdoor air processing unit from the outdoors as the outdoor air detected temperature, and an outdoor air humidity sensor that detects the relative humidity of the outdoor air sucked by the outdoor air processing unit from the outdoors as the outdoor air detected humidity, The multi-air conditioning system of claim 4, wherein when the monitoring device makes the restriction judgment, it determines whether to prioritize the selection of the indoor unit restriction control over the selection of the outdoor air unit restriction control based on at least one of the indoor temperature and humidity information of the indoor air detected temperature and the indoor air detected humidity, and the outdoor temperature and humidity information of the outdoor air detected temperature and the outdoor air detected humidity.

7. the one or more outside air processing units each include an intake fan that generates a flow of outside air from the outside of the room into the inside of the room, and an exhaust fan that generates a flow of air from the inside of the room to the outside of the room, the one or more outside air processing units are capable of ventilating the room by operating the intake air blower and the exhaust air blower, A multi-air conditioning system as described in any one of claims 1 to 6, wherein when the monitoring device forcibly switches the state of one or more outdoor air processing units to a thermo-off state, it limits the operation of the intake air blower and the exhaust air blower to limit the amount of ventilation in the room.

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