Patent Publication Number: US-2022214072-A1

Title: Fan unit, fan unit system, and air treatment system

Description:
TECHNICAL FIELD 
     The present invention relates to a fan unit including a fan with variable rotation speed, a fan unit system including the fan unit, and an air treatment system including the fan unit. 
     BACKGROUND ART 
     Patent Literature 1 (JP 2001-304614 A) discloses a main air conditioner unit having a heat exchanger coil and a fan for sending air that has been subjected to heat exchange. Each fan unit of Patent Literature 1 is connected to a plurality of outlets through a duct and the air that has been subjected to heat exchange in the single main air conditioner unit is made to flow separately to the plurality of outlets and supplied into an air-conditioning zone. 
     A controller of Patent Literature 1 controls a pump motor of a pump unit that sends a heating medium from a heat source to the heat exchanger coil and can regulate the flow rate thereof and the rotational speed of a fan motor of the plurality of fan units. Sensors are provided in the plurality of outlets, and the controller controls the air flow volume of each fan and the flow rate of the heating medium of the heat exchanger coil in accordance with variations of the total numerical value of the blow-out air flow volume signals of the sensors. 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     In the fan unit described in Patent Literature 1, one controller external to the plurality of fan units controls the rotational speed of the fan motor of the plurality of fan units. The controller of Patent Literature 1 controls the rotational speed of the fan motor of each fan unit while checking the blow-out air flow volume signals of the plurality of sensors provided in the plurality of outlets of each fan unit. This increases the control load on the controller of Patent Literature 1. 
     A fan unit whose air flow volume is controllable has a challenge of reducing the control load. 
     Solution to Problem 
     A fan unit according to a first aspect of the present invention includes a fan with variable rotation speed, an air flow volume detection unit, a unit casing, and a control unit. The air flow volume detection unit detects air flow volume of the fan or equivalent air flow volume that is a physical quantity corresponding to the air flow volume of the fan. The unit casing houses, therein, the fan and the air flow volume detection unit. The control unit controls the rotation speed of the fan. The control unit controls the rotation speed of the fan on the basis of a command value of the air flow volume of the fan given from outside the unit and a detected value of the air flow volume or the equivalent air flow volume detected by the air flow volume detection unit. 
     In the fan unit according to the first aspect of the present invention, the fan unit receives only the command value of the air flow volume, and the fan unit itself can automatically control the air flow volume. This allows the fan unit to reduce the control load, for example, simply by receiving the command value of the air flow volume appropriately from a main controller external to the fan unit. 
     A fan unit according to a second aspect of the present invention is the fan unit according to the first aspect of the present invention, and the control unit controls the rotation speed of the fan so that the air flow volume indicated in the detected value approaches the command value. 
     The fan unit according to the second aspect of the present invention easily implements automatic control of the air flow volume in the fan unit. 
     A fan unit according to a third aspect of the present invention is the fan unit according to the first or second aspect of the present invention, and the fan is a centrifugal fan. The centrifugal fan has a fan casing. The fan casing is housed in the unit casing. 
     The fan unit according to the third aspect of the present invention easily detects the air flow volume in a space that corresponds to the inside of the unit casing and also to the outside of the fan casing of the centrifugal fan, and easily performs control on the basis of the command value and the detected value of the air flow volume. 
     A fan unit according to a fourth aspect of the present invention is the fan unit according to any one of the first through third aspects, the air flow volume detection unit includes at least one of a wind speed sensor for detecting a wind speed at a predetermined location in the unit casing, a pressure sensor for detecting a static pressure in the unit casing, a differential pressure sensor for detecting a differential pressure at a predetermined location in the unit casing, and an air flow volume sensor for detecting air flow volume of the fan. 
     A fan unit according to a fifth aspect of the present invention is the fan unit according to any one of the first through fourth aspects of the present invention, and the control unit is associated with a remote controller. The command value is determined on the basis of an input of the remote controller. 
     The fan unit according to the fifth aspect of the present invention can appropriately change the air flow volume of the fan unit in accordance with the input of the remote controller. 
     A fan unit system according to a sixth aspect of the present invention includes the plurality of fan units according to any one of the first through fifth aspects of the present invention; and the main controller for sending the command value to the control unit of the fan unit. 
     An air treatment system according to a seventh aspect includes: the plurality of fan units according to any one of the first through fifth aspects; an air treatment unit connected to the plurality of fan units and configured to send treated air that has been subjected to predetermined treatment to the plurality of fan units; and the main controller for communicating with the air treatment unit and sending the command value to a control unit of the plurality of fan units. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing an outline of the configuration of an air treatment system according to a first embodiment. 
         FIG. 2  is a schematic perspective view showing an example of connection of a heat exchanger unit, a duct, a fan unit, and a blower unit. 
         FIG. 3  is a block diagram showing an example of a control system. 
         FIG. 4  is a schematic diagram showing an example of the configuration of a fan unit. 
         FIG. 5  is a schematic sectional view showing an example of a fan of a fan unit. 
         FIG. 6  is a conceptual diagram showing the configuration of an air conditioning system according to a third embodiment. 
         FIG. 7  is a block diagram for explaining the configuration of a controller of the third embodiment. 
         FIG. 8  is a block diagram for explaining the connection relationship between a main controller and a fan controller of a modification 1O. 
         FIG. 9  is a block diagram for explaining an example of the connection relationship between a main controller and a fan controller of a modification 1P. 
         FIG. 10  is a block diagram for explaining another example of the connection relationship between the main controller and the fan controller of the modification 1P. 
         FIG. 11  is a block diagram for explaining an example of the connection relationship between a main controller and a fan controller of a modification 1Q. 
         FIG. 12  is a block diagram for explaining another example of the connection relationship between the main controller and the fan controller of the modification 1Q. 
         FIG. 13  is a block diagram for explaining yet another example of the connection relationship between the main controller and the fan controller of the modification 1Q. 
         FIG. 14  is a block diagram for explaining another example of the connection relationship between a main controller and a fan controller of a modification 1R. 
         FIG. 15  is a conceptual diagram showing an example of the configuration of an air conditioning system according to a modification of the third embodiment. 
         FIG. 16  is a block diagram for explaining the configuration of a controller in  FIG. 15 . 
         FIG. 17  is a conceptual diagram showing another example of the configuration of an air conditioning system according to a modification of the third embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     (1) Overall Configuration 
     (1-1) Air Treatment System 
     An air treatment system  1  shown in  FIGS. 1 and 2  is a system that supplies conditioned air to an air conditioned space TS. The air treatment system herein is a system that applies predetermined treatment to air to be supplied to an air conditioned space. The predetermined treatment applied in the air treatment system includes filtering for removing dust particles from the air, changing air temperature, changing air humidity, filtering for removing predetermined chemical components from the air, and filtering for removing predetermined pathogens from the air. Examples of the dust particles include pollen, yellow sand, and PM 2.5. Examples of the predetermined chemical components include odorant. Examples of the pathogens include bacteria and viruses. The air treatment system  1  shown in  FIGS. 1 and 2  is, in other words, an air conditioning system that changes the temperature of outdoor air and supplies air whose temperature has been changed to the air conditioned space TS. 
     Examples of the air conditioned space TS include rooms RM 1  and RM 2  of a building BL. The rooms RM 1  and RM 2  are partitioned by a partition  78  and separated from each other. Here, a case is described in which the air conditioned space TS is the two rooms RM 1  and RM 2 , and the air treatment system  1  is adaptable to rooms of various sizes, shapes, and numbers. The air conditioned space TS to which the air treatment system  1  supplies the conditioned air is preferably surrounded by wall surfaces (front, back, top, bottom, left, and right), like the rooms RM 1  and RM 2 . Note that the air conditioned space TS is not limited to the rooms RM 1  and RM 2 , and may be, for example, a corridor, steps, and an entrance. The air conditioned space TS may be, for example, one space such as a large hall, or a plurality of independent spaces such as a plurality of rooms separated from one another. 
     As shown in  FIG. 1 , the air treatment system  1  includes a heat exchanger unit  10 , a plurality of ducts  20 , a plurality of fan units  30 , and a controller  400  (see  FIG. 3 ). The heat exchanger unit  10  is an air treatment unit. 
     The air treatment system  1  generates conditioned air through heat exchange in the heat exchanger unit  10  to supply the conditioned air thus generated to the air conditioned space TS through a plurality of distribution flow paths. Each of the plurality of ducts  20  is disposed in one of the plurality of distribution flow paths. The air treatment system  1  includes a plurality of openings  71  disposed in the air conditioned space TS so that the plurality of openings  71  correspond to the plurality of ducts  20 . Each fan unit  30  supplies the conditioned air to the corresponding openings  71 . Each of the plurality of fan units  30  is disposed in one of the plurality of distribution flow paths. 
     Note that the plurality of ducts  20  is sometimes distinguished from one another, such as a duct  20   a , by giving alphabetic subscripts to the plurality of ducts  20 . Here, four ducts  20   a  to  20   d  are shown as the ducts  20 . Further, four fan units  30   a  to  30   d  are shown as the fan units  30 . Further, four blower units  70   a  to  70   d  and remote controllers  60   a  to  60   d  are shown as a blower unit  70  and a remote controller  60 , respectively. Each of the plurality of blower units  70   a  to  70   d  is disposed in one of the plurality of distribution flow paths. 
     The heat exchanger unit  10  includes a use side heat exchanger  11 . The heat exchanger unit  10  has a function to change an air temperature through heat exchange in the use side heat exchanger  11 . The air whose temperature has been changed by the use side heat exchanger  11  is the conditioned air. The heat exchanger unit  10  transfers heat between air sucked into and a refrigerant to blow out the conditioned air. 
     The plurality of ducts  20  has one end  21  connected to the heat exchanger unit  10 . The plurality of ducts  20  is a plurality of pipes to send the conditioned air generated by the heat exchanger unit  10 , and has a function to distribute the conditioned air. In other words, the plurality of ducts  20  serves to distribute the conditioned air that has passed through the use side heat exchanger  11  of the heat exchanger unit  10 . The plurality of ducts  20  has other end  22  connected to the plurality of fan units  30 , and the conditioned air sent from the ducts  20  is supplied through the fan unit  30  and the blower unit  70  to the air conditioned space TS. 
     The plurality of fan units  30  is connected to the other ends  22  of the plurality of ducts  20 . Here, for example, one duct  20   a  connected to the heat exchanger unit  10  is connected to one corresponding fan unit  30   a . Similarly, the fan units  30   b  to  30   d  are connected to the corresponding ducts  20   b  to  20   d , respectively. A description is given of a case where each duct  20  has one end  21  and one other end  22 ; however, one duct  20  may be branched to have one end  21  and a plurality of other ends  22 , and the fan units  30  may be connected to the plurality of other ends  22  thus branched, respectively. Further, the fan units  30   a  to  30   d  are connected to the blower units  70   a  to  70   d  and the remote controllers  60   a  to  60   d , respectively. 
     In order to supply the conditioned air to the openings  71 , the fan units  30  suck in the conditioned air from the heat exchanger unit  10  through the ducts  20 . Each of the fan units  30  includes a fan  32  in a unit casing  31  thereof to suck in the conditioned air. The fan  32  sends air from the other end  22  of the duct  20  toward the opening  71 . The number of fans  32  of each of the fan units  30  may be one or more. Here, fans  32   a  to  32   d  are provided in the unit casings  31  of the fan units  30   a  to  30   d , respectively. 
     The fan units  30  are configured to change the amount of conditioned air supplied to the openings  71 . The amount of air supplied is the amount of air supplied to the air conditioned space TS per unit time. Here, four fan motors  38   a  to  38   d  are configured to change the rotation speed individually. The fan motors  38   a  to  38   d  change the rotation speed individually, which enables the fan units  30   a  to  30   d  to change the amount of air supplied individually. 
     The controller  400  controls the plurality of fan units  30 . More specifically, a main controller  40  of the controller  400  sends, to the plurality of fan units  30 , a plurality of commands concerning the amount of air supplied. For example, the main controller  40  sends, to the fan units  30 , a command value of the air flow volume of the fan units  30 . The command value of the air flow volume may be, for example, a value of the air flow volume (CMH), a value of the wind speed (m/s) for the case where the cross-sectional area through which the air passes is known, or a static pressure (Pa), provided the relationship between the air flow volume and the static pressure is determined. 
     In addition to the configuration described above, the air treatment system  1  includes a heat source unit  50 , the remote controller  60 , the blower unit  70 , a suction unit  80 , and various sensors. Such sensors are preferably sensors corresponding to the command value of the air flow volume of the main controller  40 , which simplifies the control. The sensors of the air treatment system  1  are detailed later. Further, a control system of the air treatment system  1  including the main controller  40  of the controller  400  is described later. 
     (2) Detailed Configuration 
     (2-1) Heat Exchanger Unit  10   
     The heat exchanger unit  10  includes the use side heat exchanger  11 , a hollow housing  12  for housing the use side heat exchanger  11  therein, and the main controller  40 . The housing  12  has one air inlet  12   a  connected to a suction port  81  and a plurality of air outlets  12   b  connected to the plurality of ducts  20 . Here, the case of one air inlet  12   a  is shown; however, a plurality of air inlets  12   a  may be provided. Further, the case where the suction port  81  is provided in the room RM is described herein; however, the suction port  81  may be provided outside the building BL, for example. In a case where the suction port  81  is provided outside the building BL, a flow path for exhausting air from the air conditioned space TS to the outside of the building BL is provided so that the air pressure in the air conditioned space TS is substantially constant regardless of the amount of air supplied. 
     The use side heat exchanger  11  is, for example, a fin-and-tube heat exchanger, and transfers heat between the refrigerant flowing in a heat transfer tube and air passing between the heat transfer fins. When air sucked in from the air inlet  12   a  passes through the use side heat exchanger  11 , heat is transferred between the air and the refrigerant (heating medium) passing through the use side heat exchanger  11  to generate conditioned air. The conditioned air generated in the use side heat exchanger  11  is sucked into the ducts  20   a  to  20   b  from the air outlets  12   b.    
     The heat exchanger unit  10  has no fan. The reason why the heat exchanger unit  10  can suck in air from the air inlet  12   a  is that a negative pressure is exerted inside the heat exchanger unit  10  in response to all the plurality of ducts  20  sucking in air from the plurality of air outlets  12   b . As described above, since the heat exchanger unit  10  has no function to send out air, it is important to prevent backflow from the duct  20  to the heat exchanger unit  10 . In order to prevent backflow of the conditioned air, for example, the static pressure at one end  21  (inlet) of all the ducts  20  is kept higher than the static pressure in the heat exchanger unit  10 . Alternatively, in order to prevent backflow of the conditioned air, for example, in a case where both the fan unit  30  with the fan motor  38  driving and the fan unit  30  with the fan motor  38  stopped are present, the air flow path in which the fan unit  30  with the fan motor  38  stopped is disposed is closed. 
     The heat exchanger unit  10  is provided with an in-unit refrigerant pipe  131  connecting the use side heat exchanger  11  and a refrigerant connection pipe  91  and an in-unit refrigerant pipe  132  connecting the use side heat exchanger  11  and a refrigerant connection pipe  92 . One inlet and outlet of the use side heat exchanger  11  is connected to the in-unit refrigerant pipe  131 . The other inlet and outlet of the use side heat exchanger  11  is connected to the in-unit refrigerant pipe  132 . 
     (2-2) Duct  20   
     The plurality of ducts  20  having a function to distribute the conditioned air connects the plurality of air outlets  12   b  of the heat exchanger unit  10  and the plurality of fan units  30 . A case where the fan units  30  are directly connected to the blower units  70  is described herein; however, the ducts  20  may be disposed between the fan units  30  and the blower units  70  so that the fan units  30  and the blower units  70  are connected to each other by the ducts  20 . 
     The duct  20  is, for example, a ventilation path with a rectangular or round cross section made of a steel plate or another material. The duct  20  may be a metal pipe having a fixed shape or a pipe made of a freely bendable material. Connecting such ducts  20  enables various arrangements of the heat exchanger unit  10 , the plurality of fan units  30 , and the plurality of blower units  70 . 
       FIG. 2  is a perspective view conceptually showing the heat exchanger unit  10 , the four fan units  30 , and the four blower units  70  connected to one another in a ceiling room AT. Since it is easy to make the heat exchanger unit  10 , the fan units  30 , and the blower units  70  configured as described above thin, the heat exchanger unit  10 , the fan units  30 , and the blower units  70  may be disposed in a space under the floor of the rooms RM 1  and RM 2 . 
     (2-3) Heat Source Unit  50   
     The heat source unit  50  supplies heat energy required for heat exchange of the use side heat exchanger  11  of the heat exchanger unit  10 . In the air treatment system  1  shown in  FIG. 1 , a refrigerant circulates between the heat source unit  50  and the heat exchanger unit  10 , and a vapor compression refrigeration cycle is performed. The heat source unit  50  and the heat exchanger unit  10  constitute a refrigeration cycle apparatus that performs the vapor compression refrigeration cycle. In the example shown in  FIG. 1 , the heat source unit  50  is placed outside the building BL and uses the outside air as a heat source; however, the installation location of the heat source unit  50  is not limited to the outside the building BL. 
     The heat source unit  50  includes a compressor  51 , a heat source side heat exchanger  52 , an expansion valve  53 , a four-way valve  54 , a heat source-side fan  55 , a heat source controller  56 , and in-unit refrigerant pipes  57  and  58 . A discharge port of the compressor  51  is connected to a first port of the four-way valve  54 , and a suction port of the compressor  51  is connected to a third port of the four-way valve  54 . The compressor  51  compresses the refrigerant in a gas state (hereinafter, also referred to as a gas refrigerant) sucked in from the suction port or the refrigerant in a gas-liquid two-phase state to discharge the compressed refrigerant from the discharge port. The compressor  51  contains a compressor motor capable of changing the rotation speed (or an operating frequency) by inverter control, for example. The compressor  51  can change the discharge amount, per unit time, of the refrigerant to be discharged by changing the operating frequency. 
     The four-way valve  54  connects one inlet and outlet of the heat source side heat exchanger  52  to a second port and connects the in-unit refrigerant pipe  58  to a fourth port. 
     During a cooling operation, as indicated by a solid line, the four-way valve  54  causes the refrigerant to flow from the first port to the second port, and thereby sends the refrigerant discharged from the compressor  51  to the heat source side heat exchanger  52 . During the cooling operation, the four-way valve  54  also causes the refrigerant to flow from the fourth port to the third port, and thereby sends the refrigerant flowing out of the use side heat exchanger  11  to the suction port of the compressor  51  through the in-unit refrigerant pipe  132 , the refrigerant connection pipe  92 , and the in-unit refrigerant pipe  58 . 
     During a heating operation, as indicated by a broken line, the four-way valve  54  causes the refrigerant to flow from the first port to the fourth port, and thereby sends the refrigerant discharged from the compressor  51  to the use side heat exchanger  11  through the in-unit refrigerant pipe  58 , the refrigerant connection pipe  92 , and the in-unit refrigerant pipe  132 . During the heating operation, the four-way valve  54  also causes the refrigerant to flow from the second port to the third port, and thereby sends the refrigerant flowing out of the heat source side heat exchanger  52  to the suction port of the compressor  51 . The heat source side heat exchanger  52  is, for example, a fin-and-tube heat exchanger, and transfers heat between the refrigerant flowing in a heat transfer tube and air passing between the heat transfer fins. 
     The other inlet and outlet of the heat source side heat exchanger  52  is connected to one end of the expansion valve  53 . The other end of the expansion valve  53  is connected to one inlet and outlet of the use side heat exchanger  11  through the in-unit refrigerant pipe  57 , the refrigerant connection pipe  91 , and the in-unit refrigerant pipe  131 . 
     The heat source unit  50  and the heat exchanger unit  10  are connected to each other to constitute a refrigerant circuit  200 . In the refrigerant circuit  200 , during the cooling operation, the refrigerant flows in the order of the compressor  51 , the four-way valve  54 , the heat source side heat exchanger  52 , the expansion valve  53 , the use side heat exchanger  11 , the four-way valve  54 , and the compressor  51 . Further, during the heating operation, in the refrigerant circuit  200 , the refrigerant flows in the order of the compressor  51 , the four-way valve  54 , the use side heat exchanger  11 , the expansion valve  53 , the heat source side heat exchanger  52 , the four-way valve  54 , and the compressor  51 . 
     (2-3-1) Circulation of Refrigerant During Cooling Operation 
     During the cooling operation, a gas refrigerant compressed by the compressor  51  is sent to the heat source side heat exchanger  52  through the four-way valve  54 . The heat of the refrigerant is dissipated by the heat source side heat exchanger  52  to the air moved by the heat source-side fan  55 , is decompressed and expanded by the expansion valve  53 , and is sent to the use side heat exchanger  11  through the in-unit refrigerant pipe  57 , the refrigerant connection pipe  91 , and the in-unit refrigerant pipe  131 . The refrigerant having a low temperature and low pressure sent from the expansion valve  53  to the use side heat exchanger  11  takes heat from the air sent from the suction port  81  through the heat exchange in the use side heat exchanger  11 . The gas refrigerant or the gas-liquid two-phase refrigerant that has been subjected to the heat exchange in the use side heat exchanger  11  is sucked into the compressor  51  through the in-unit refrigerant pipe  132 , the refrigerant connection pipe  92 , the in-unit refrigerant pipe  58 , and the four-way valve  54 . The conditioned air whose heat has been transferred by the use side heat exchanger  11  is blown out to the rooms RM 1  and RM 2  through the plurality of ducts  20 , the plurality of fan units  30 , and the plurality of openings  71 , which cools the rooms RM 1  and RM 2 . 
     During the cooling operation, the heat source controller  56  adjusts, for example, the opening degree of the expansion valve  53  to match the degree of superheating of the refrigerant sucked into the suction port of the compressor  51  to a target value of the degree of superheating in order to prevent liquid compression in the compressor  51 . The heat source controller  56  also controls the compressor  51  to change the operating frequency to handle the cooling load while adjusting the opening degree of the expansion valve  53 . The degree of superheating is calculated, for example, by subtracting an evaporation temperature of the refrigerant in the use side heat exchanger  11  from the temperature of the gas refrigerant flowing out of the use side heat exchanger  11 . 
     (2-3-2) Circulation of Refrigerant During Heating Operation 
     During the heating operation, a gas refrigerant compressed by compressor  51  passes through the four-way valve  54 , the in-unit refrigerant pipe  58 , the refrigerant connection pipe  92 , and the in-unit refrigerant pipe  132  and is sent to the use side heat exchanger  11 . The refrigerant is subjected to the heat exchange in the use side heat exchanger  11  and gives heat to the air sent from the suction port  81 . The refrigerant that has been subjected to the heat exchange in the use side heat exchanger  11  passes through the in-unit refrigerant pipe  131 , the refrigerant connection pipe  91 , and the in-unit refrigerant pipe  57  and is sent to the expansion valve  53 . The refrigerant having a low temperature and low pressure decompressed and expanded by the expansion valve  53  is sent to the heat source side heat exchanger  52 , and absorbs heat from air moved by the heat source-side fan  55  through the heat exchange in the heat source side heat exchanger  52 . The gas refrigerant or the gas-liquid two-phase refrigerant that has been subjected to the heat exchange in the heat source side heat exchanger  52  passes through the four-way valve  54  and is sucked into the compressor  51 . The conditioned air given heat in the use side heat exchanger  11  passes through the plurality of ducts  20 , the plurality of fan units  30 , and the plurality of openings  71  to be blown out to the rooms RM 1  and RM 2 , which heats the rooms RM 1  and RM 2 . 
     During the heating operation, for example, the heat source controller  56  adjusts the opening degree of the expansion valve  53  so that the degree of subcooling of the refrigerant at the outlet of the use side heat exchanger  11  (in-unit refrigerant pipe  131 ) matches a target value. The heat source controller  56  also controls the compressor  51  to change the operating frequency to handle the heating load while adjusting the opening degree of the expansion valve  53 . The degree of subcooling of the use side heat exchanger  11  is calculated, for example, by subtracting the temperature of the liquid refrigerant flowing out of the use side heat exchanger  11  from a condensation temperature of the refrigerant in the use side heat exchanger  11 . 
     The blower unit  70  is mounted, for example, on a ceiling CE with the opening  71  facing downward. The case where the blower unit  70  is mounted on the ceiling CE is shown as an example herein. However, for example, the blower unit  70  may be mounted on the wall, and the location at which the blower unit  70  is mounted is not limited to the ceiling CE. 
     (2-4) Blower Unit  70   
     The blower unit  70  includes an air filter  73  in a hollow casing  72 . The blower unit  70  blows out the conditioned air, sent from the fan unit  30 , from the opening  71  through the air filter  73 . The blower units  70   a  to  70   d  are thus connected to the fan units  30   a  to  30   d , respectively. The case where the blower unit  70  includes the air filter  73  is described herein; however, the blower unit  70  may be configured without the air filter  73 . 
     The blower unit  70  includes an air deflector  74  in the hollow housing  72 . The blower unit  70  includes an air deflector motor  75  for driving the air deflector  74 . The air deflector motor  75  rotates and moves the air deflector  74 , which enables the air deflector  74  to adjust the airflow direction. Further, the air deflector  74  can move to a position at which the opening  71  is tightened up. The air deflector motor  75  is connected to, for example, a fan controller  34  of the fan unit  30 . The fan controller  34  is thus a control unit that controls the airflow direction of the blower unit  70  and the opening and closing of the opening  71 . The case where the blower unit  70  includes the air deflector  74  and the air deflector motor  75  is described herein; however, the blower unit  70  may be configured without the air deflector  74  and the air deflector motor  75 . Another configuration is possible in which the main controller  40  controls the airflow direction of all the blower units  70  and the opening and closing of the opening  71 . 
     The suction unit  80  is mounted on the ceiling CE of the building BL with the suction port  81  facing the air conditioned space TS, for example. The case where the suction unit  80  is mounted on the ceiling CE of the building BL is shown as an example herein; however, for example, the suction unit  80  does not have to be mounted on the ceiling CE of the building BL. For example, the location at which the suction unit  80  is mounted may be a wall of the building BL. 
     The suction unit  80  includes an air filter  83  in a hollow housing  82 . The suction unit  80  takes in air to be sent to the heat exchanger unit  10  from the suction port  81  through the air filter  83 . The case where the suction unit  80  includes the air filter  83  is described herein; however, the suction unit  80  may be configured without the air filter  83 . 
     (2-5) Fan Unit  30   
     As shown in  FIG. 4 , each of the fan units  30  includes the unit casing  31 , the fan  32 , an air flow volume detection unit  33 , and the fan controller  34 . The fan unit  30  is one product in which the fan  32 , the air flow volume detection unit  33 , and the fan controller  34  are attached to the unit casing  31 . Each unit casing  31  has an intake port  36  and an outlet  37 . The unit casing  31  is a housing having a space of a predetermined shape through which air entering from the intake port  36  and exiting from the outlet  37  passes. The intake port  36  of each unit casing  31  is connected to the other end  22  of each duct  20 . The outlet  37  of each unit casing  31  is connected to an outlet of each fan  32 , and also connected to the corresponding blower unit  70 . The conditioned air blown out from the fan  32  passes through the blower unit  70  and is blown out from the opening  71 . 
     Each unit casing  31  houses, therein, the fan  32  and the air flow volume detection unit  33 . The fan  32  includes a fan casing  39  (see  FIG. 5 ). The rotation speed of each fan  32  can be changed. The fan  32  is fixed at a predetermined position in the unit casing  31 , and an outlet  39   b  of the fan casing  39  is connected to the outlet  37  of the unit casing  31 . An inlet  39   a  of the fan casing  39  is provided at a predetermined position of the internal space of the unit casing  31 . For example, a centrifugal fan can be used as the fan  32 . Examples of the centrifugal fan used as the fan  32  include a sirocco fan.  FIG. 5  is a sectional view showing the sirocco fan as an example of the fan  32 . The fan  32  houses a fan rotor  35  in the fan casing  39  so that the fan rotor  35  can rotate. The fan motor  38  rotates the fan rotor  35  of the sirocco fan. The rotation speed of the fan  32  can be rephrased as the rotation speed of the fan rotor  35 . Increasing the rotation speed of the fan motor  38  increases the rotation speed of the fan rotor  35 , so that the fan  32  increases the air flow volume. In addition, reducing the rotation speed of the fan motor  38  reduces the rotation speed of the fan rotor  35 , so that the fan  32  reduces the air flow volume. Since the outlet of the fan  32  is connected to the outlet  37  of the unit casing  31 , the air flow volume of the fan  32  matches the amount of air supplied from the opening  71 . The fan  32  can, therefore, change the amount of air supplied by changing the rotation speed of the fan motor  38 . 
     The fan controller  34  is attached to the unit casing  31 . All the fan controllers  34  are connected to the main controller  40  herein. The fan controller  34  is connected to the fan motor  38 , so that the fan controller  34  can control the rotation speed of the fan motor  38 . 
     The air flow volume detection unit  33  of each fan unit  30  detects air flow volume of the fan  32  or equivalent air flow volume that is a physical quantity corresponding to the air flow volume of the fan  32 . In detecting the air flow volume of the fan  32 , the air flow volume detection unit  33  includes an air flow volume sensor. In detecting the equivalent air flow volume that is a physical quantity corresponding to the air flow volume of the fan  32 , the air flow volume detection unit  33  includes, for example, a wind speed sensor, a differential pressure sensor, or a pressure sensor. In detecting the air flow volume with an air flow volume sensor, the air flow volume sensor is installed at a predetermined position in the unit casing  31 . Since shapes and positions of the unit casing  31 , the fan  32 , the intake port  36 , the outlet  37 , and the air flow volume sensor are determined, a relationship between a measured value of the installed air flow volume sensor and the air flow volume of the fan  32  is checked by an experiment. The fan controller  34  stores, for example, a table showing the relationship between the measured value of the air flow volume sensor and the air flow volume of the fan  32 . 
     Further, in detecting the wind speed as the equivalent air flow volume, the air flow volume detection unit  33  includes a wind speed sensor that detects a wind speed at a predetermined position in the unit casing  31 . Since shapes and positions of the unit casing  31 , the fan  32 , the intake port  36 , the outlet  37 , and the wind speed sensor are determined, a relationship between a measured value of the installed wind speed sensor and the air flow volume of the fan  32  is checked by an experiment. The fan controller  34  stores, for example, a table showing the relationship between the measured value of the wind speed sensor and the air flow volume of the fan  32 . 
     Further, in detecting the differential pressure as the equivalent air flow volume, the air flow volume detection unit  33  includes a differential pressure sensor that detects a difference between static pressures at two predetermined locations in the unit casing  31 . Since shapes and positions of the unit casing  31 , the fan  32 , the intake port  36 , the outlet  37 , and the differential pressure sensor are determined, a relationship between a measured value of the installed differential pressure sensor and the air flow volume of the fan  32  is checked by an experiment. The fan controller  34  stores, for example, a table showing the relationship between the measured value of the differential pressure sensor and the air flow volume of the fan  32 . 
     Further, in detecting the static pressure as the equivalent air flow volume, the air flow volume detection unit  33  includes a pressure sensor that detects a static pressure at a predetermined location in the unit casing  31 . Since shapes and positions of the unit casing  31 , the fan  32 , the intake port  36 , the outlet  37 , and the pressure sensor are determined, a relationship between a measured value of the installed pressure sensor and the air flow volume of the fan  32  is checked by an experiment. The fan controller  34  stores, for example, a table showing the relationship between the measured value of the pressure sensor and the air flow volume of the fan  32 . 
     Note that the method for determining the air flow volume on the basis of the measured value is not limited to the method of using the table for conversion to the air flow volume, and instead of the table, the fan controller  34  may be configured to, for example, use a relational expression showing the relationship between each parameter and the air flow volume to calculate the air flow volume on the basis of the measured value. 
     The fan controller  34  receives, from the main controller  40 , a command value of the air flow volume of the fan  32 . The fan controller  34  controls the rotation speed of the fan  32  on the basis of the command value of the air flow volume and a detected value of the air flow volume or the equivalent air flow volume detected by the air flow volume detection unit  33 . The fan controller  34  controls, for example, the rotation speed of the fan  32  so that the air flow volume indicated in the detected value approaches the command value. Specifically, the fan controller  34  reduces the rotation speed of the fan  32  if the air flow volume indicated in the detected value is greater than the command value, and increases the rotation speed of the fan  32  if the air flow volume indicated in the detected value is smaller than the command value. 
     The fan controller  34  is associated with, for example, the remote controller  60 . For example, in a case where a set temperature is inputted to the remote controller  60 , the main controller  40  sends, to the fan controller  34  of the fan unit  30 , a command value in accordance with the set temperature inputted to the remote controller  60 . To that end, the main controller  40  determines the command value on the basis of the set temperature that is an input of the remote controller  60 . For example, during the cooling operation, in a case where the set temperature of the remote controller  60  is higher than a room temperature detected by the remote controller  60 , a command value is sent which is smaller than the command value for the case of the room temperature matching the set temperature. Conversely, during the cooling operation, in a case where the set temperature of the remote controller  60  is lower than the room temperature, a command value is sent which is larger than the command value for the case of the room temperature matching the set temperature. For example, in a case where the fan controller  34  which has received the command value for the case of the room temperature matching the set temperature receives a command value larger than that command value, the rotation speed of the fan  32  is increased to increase the air flow volume of the fan  32 . 
     (2-6) Control System 
     As shown in  FIG. 3 , the main controller  40  is connected to the plurality of fan controllers  34  and the heat source controller  56 . The heat source controller  56  includes, for example, various circuits provided on a printed wiring board connected to various devices of the heat source unit  50 , and controls the various devices of the heat source unit  50  such as the compressor  51 , the expansion valve  53 , the four-way valve  54 , and the heat source-side fan  55 . The main controller  40  is also connected to the remote controllers  60  through the fan controllers  34 . The remote controllers  60   a  to  60   d  correspond to the blower units  70   a  to  70   d  respectively, and are connected to the fan units  30   a  to  30   d  respectively. The case where the remote controller  60  is connected to the main controller  40  through the fan controllers  34  is described herein; however, the remote controller  60  may be directly connected to the main controller  40 . Further, the case where the main controller  40 , the plurality of fan controllers  34 , the heat source controller  56 , and the plurality of remote controllers  60  are connected by wire is shown herein; however, all or some of them may be connected by wireless communication. 
     The main controller  40  and the plurality of fan units  30  may be combined into one product as a set of fan unit systems  300  (see  FIG. 3 ). In a case where the main controller  40  and the plurality of fan units  30  are provided as the fan unit system  300  as described above, the control program for the main controller  40  and the plurality of fan units  30  can be easily constructed in a factory or the like. This makes it easy to omit extra functions, which simplifies the system. 
     Each of the main controller  40 , the plurality of fan controllers  34 , the heat source controller  56 , and the plurality of remote controllers  60  is implemented by, for example, a computer. The computer constituting the main controller  40 , the plurality of fan controllers  34 , the heat source controller  56 , and the plurality of remote controllers  60  includes a control computing device and a storage device. The control computing device may be a processor such as a CPU or a GPU. The control computing device reads out a program stored in the storage device and performs predetermined image processing and computing processing in accordance with the program. Further, the control computing device can write an computing result to the storage device and read out information stored in the storage device in accordance with the program. However, the main controller  40 , the plurality of fan controllers  34 , the heat source controller  56 , and the plurality of remote controllers  60  may be configured using an integrated circuit (IC) capable of performing control similar to that performed using a CPU and a memory. Examples of the IC herein include a large-scale integrated circuit (LSI), an application-specific integrated circuit (ASIC), a gate array, and a field programmable gate array (FPGA). 
     The heat exchanger unit  10  includes a suction temperature sensor  101 , a gas pipe temperature sensor  102 , a liquid pipe temperature sensor  103 , and a use side heat exchanger temperature sensor  104 . Note that, for example, these temperature sensors or a temperature sensor described later may be thermistors. The suction temperature sensor  101 , the gas pipe temperature sensor  102 , the liquid pipe temperature sensor  103 , and the use side heat exchanger temperature sensor  104  are connected to the main controller  40 , and detection results thereof are sent to the main controller  40 . The suction temperature sensor  101  detects the temperature of air sucked in from the air inlet  12   a . The gas pipe temperature sensor  102  detects the temperature of a refrigerant at one inlet and outlet of the use side heat exchanger  11  connected to the in-unit refrigerant pipe  132 . The liquid pipe temperature sensor  103  detects the temperature of a refrigerant at the other inlet and outlet of the use side heat exchanger  11  connected to the in-unit refrigerant pipe  131 . The use side heat exchanger temperature sensor  104  is mounted in the vicinity of the middle of a refrigerant flow path in the use side heat exchanger  11 , and detects the temperature of a refrigerant in the gas-liquid two-phase state flowing through the use side heat exchanger  11 . The main controller  40  uses a detected value of at least one of the suction temperature sensor  101 , the gas pipe temperature sensor  102 , the liquid pipe temperature sensor  103 , and the use side heat exchanger temperature sensor  104  to determine a command concerning an increase or decrease in the amount of air supplied. Note that an air outlet temperature sensor  105  that detects the temperature of air that has just passed through the use side heat exchanger  11  may be provided. 
     The heat source unit  50  includes a heat source-side air temperature sensor  111 , a discharge pipe temperature sensor  112 , and a heat source side heat exchanger temperature sensor  113 . The heat source-side air temperature sensor  111 , the discharge pipe temperature sensor  112 , and the heat source side heat exchanger temperature sensor  113  are connected to the heat source controller  56 . The detection results of the heat source-side air temperature sensor  111 , the discharge pipe temperature sensor  112 , and the heat source side heat exchanger temperature sensor  113  are sent to the main controller  40  through the heat source controller  56 . The heat source-side air temperature sensor  111  detects the temperature of airflow produced by the heat source-side fan  55  before passing through the heat source side heat exchanger  52 . The discharge pipe temperature sensor  112  detects the temperature of the refrigerant discharged from the compressor  51 . The heat source side heat exchanger temperature sensor  113  is mounted in the vicinity of the middle of a refrigerant flow path in the heat source side heat exchanger  52 , and detects the temperature of a refrigerant in the gas-liquid two-phase state flowing through the heat source side heat exchanger  52 . 
     The fan unit  30  includes the air flow volume detection unit  33  and a blow-out temperature sensor  122 . The air flow volume detection unit  33  detects, for example, volume of air passing through the unit casing  31  of the fan unit  30 . The air flow volume detection unit  33  is connected to the fan controller  34  and sends data on the detected value to the fan controller  34 . Note that the air flow volume detection unit  33  may be configured to detect the airflow direction so that backflow can be detected. The blow-out temperature sensor  122  is installed in the unit casing  31  of each fan unit  30 , for example, and detects the temperature of the conditioned air blown out from each fan unit  30 . The case where the blow-out temperature sensor  122  is installed in the unit casing  31  is described herein; however, the installation location of the blow-out temperature sensor  122  may be another place, for example, may be inside the blower unit  70 . 
     Each of the plurality of remote controllers  60  contains an indoor temperature sensor  61 , and is configured to input a command to turn on and off the operation of the air treatment system  1  and/or the fan unit  30 , switching between air-cooling and air-heating, and a set temperature. The set temperature can be inputted as a numerical value, for example. For example, a user uses an input button on the remote controller  60  to select cooling operation, set the set temperature at 28° C., and select medium airflow as the set air flow volume. 
     The main controller  40  calculates the amount of air supplied necessary to be blown out from each fan unit  30  on the basis of the blow-out temperature detected by each blow-out temperature sensor  122  and the set temperature, and sends a command value to the fan controller  34 . Note that the case where the indoor temperature sensor  61  is contained in the remote controller  60  is described herein; however, the position at which the indoor temperature sensor  61  is provided is not limited to the remote controller  60 . For example, a configuration is possible in which an indoor temperature sensor is present as a single independent device, and the main controller  40  receives a value of room temperature from the independent indoor temperature sensor. 
     Second Embodiment 
     (3) Overall Configuration 
     The main controller  40  controls a plurality of actuators in accordance with a plurality of commands concerning the amount of air supplied by the plurality of fan units  30 . This type of form is not limited to the form of the first embodiment. The air treatment system  1  in which the main controller  40  controls the plurality of actuators in accordance with a plurality of commands concerning the amount of air supplied by the plurality of fan units  30  may be configured as described in the second embodiment. In the air treatment system  1  of the second embodiment, the plurality of fan controllers  34 , which is a plurality of sub controllers, receives a plurality of commands sent by the main controller  40 . In the air treatment system  1  of the second embodiment, each of the plurality of fan controllers  34  controls at least one of the plurality of actuators on the basis of at least one of the plurality of commands. 
     Specifically, the following describes an example in which the air treatment system  1  of the second embodiment has the configuration shown in  FIG. 1  as with the air treatment system  1  of the first embodiment. In the second embodiment, a case is described in which the air treatment system  1  shown in  FIG. 1  changes the amount of air supplied with the fan motor  38  and the air deflector  74  is not involved in changing the amount of air supplied. 
     As with the main controller  40  of the first embodiment, the main controller  40  of the second embodiment calculates the amount of air supplied necessary to be blown out from each fan unit  30  on the basis of the blow-out temperature detected by each blow-out temperature sensor  122  and the set temperature. Specifically, for example, the main controller  40  calculates the amount of air supplied by each of the fan units  30   a  to  30   d  on the basis of the temperature difference between the indoor air temperature to be adjusted by each of the plurality of fan units  30   a  to  30   d  and the set temperature and the blowing temperature. The main controller  40  determines the calculated amount of air supplied (target air supply amount) of each of the fan units  30   a  to  30   d  as a command to be given to the fan units  30   a  to  30   d.    
     The main controller  40  sends, to the plurality of fan controllers  34 , the plurality of calculated amounts of air supplied as the target air supply amount. In other words, the main controller  40  sends a plurality of commands to the plurality of fan controllers  34  for controlling the fan units  30   a  to  30   d . The main controller  40  sends, for example, to the fan controller  34  attached to the fan unit  30   a , the target air supply amount of the fan unit  30   a . The target air supply amount of the fan unit  30   a  is a command concerning the amount of air supplied by the fan unit  30 . The fan controller  34  of the fan unit  30   a  controls the rotation speed of the fan motor  38   a  so as to bring the amount of air supplied closer to the target air supply amount. Similarly, the main controller  40  sends, to the fan controller  34  attached to the fan units  30   b  to  30   d , the target air supply amount of the fan units  30   b  to  30   d . The fan controller  34  of the fan units  30   b  to  30   d  controls the fan motors  38   b  to  38   d  so as to bring the amount of air supplied closer to the target air supply amount. 
     More specifically, each of the fan units  30   a  to  30   d  includes a differential pressure sensor as the air flow volume detection unit  33  that detects volume of air passing through the unit. Note that the air flow volume detection unit  33  is not limited to the differential pressure sensor. For example, the air flow volume detection unit  33  may be a wind speed sensor. For example, the fan controller  34  of the fan unit  30   a  compares the volume of air (amount of air supplied) passing through the fan unit  30   a  detected by the differential pressure sensor of the fan unit  30   a  with a target air flow volume (target air supply amount). In a case where the volume of the air passing through the fan unit  30   a  is smaller than the target air flow volume, the fan controller  34  of the fan unit  30   a  increases the rotation speed of the fan motor  38   a  and increases the air flow volume (amount of air supplied) of the fan unit  30   a  to bring the air flow volume closer to the target air flow volume. Conversely, in a case where the volume of the air passing through the fan unit  30   a  is greater than the target air flow volume, the fan controller  34  of the fan unit  30   a  reduces the rotation speed of the fan motor  38   a  and reduces the air flow volume (amount of air supplied) of the fan unit  30   a  to bring the air flow volume closer to the target air flow volume. 
     The case where the fan controller  34  is attached to the fan unit  30  is described herein. However, it is possible that the fan controller  34  is not attached to the fan unit  30 . 
     Third Embodiment 
     (4) Overall Configuration 
     The air treatment system  1  shown in  FIG. 6  includes the heat exchanger unit  10 , the fan unit  30 , the duct  20 , and the controller  400 . The heat exchanger unit  10  includes a blower  29 . Each of a plurality of fan units  30  includes the fan  32 . Each fan  32  supplies air from the fan unit  30  to the air conditioned space TS. The air conditioned space TS is, for example, a room in a building. The room is, for example, a space in which air movement is limited by a floor, a ceiling, and a wall. The plurality of fan units  30  is disposed in one or more of the air conditioned spaces TS.  FIG. 6  is a diagram showing an example in which, as a representative example of the air treatment system  1  including the plurality of fan units  30 , the air treatment system  1  including two fan units  30  is disposed in one air conditioned space TS. The number of fan units  30  may be three or more, and is appropriately set. As described above, the number of air conditioned spaces TS in which the fan unit  30  is disposed may be two or more. 
     The duct  20  distributes air SA, sent out from the heat exchanger unit  10  by the blower  29 , to the plurality of fan units  30 . The duct  20  includes a main pipe  26  and a branch pipe  27  that branches off from the main pipe  26 .  FIG. 6  is a diagram showing a case where the main pipe  26  is disposed outside the heat exchanger unit  10 ; however, the main pipe  26  may be disposed in the heat exchanger unit  10  and may be disposed to extend from the inside of the heat exchanger unit  10  to the outside thereof. The case where the main pipe  26  is disposed in the heat exchanger unit  10  also includes a case where a part of a casing of the heat exchanger unit  10  functions as the main pipe  26 .  FIG. 6  is a diagram showing an example in which an inlet  26   a  of the main pipe  26  is connected to the heat exchanger unit  10 . The blower  29  is disposed in the heat exchanger unit  10 . Herein, all the air blown out from the blower  29  flows into the duct  20 . 
     An outlet  26   b  of the main pipe  26  of the duct  20  is connected to an inlet  27   a  of the branch pipe  27 . A plurality of outlets  27   b  of the branch pipe  27  is connected to the plurality of fan units  30 . 
     Each fan unit  30  is connected to the air conditioned space TS by a ventilation path  181 . An inlet  181   a  of the ventilation path  181  is connected to the fan unit  30 . Each fan  32  produces airflow from the outlet  27   b  of the duct  20  toward the inlet  181   a  of the ventilation path  181  in the fan unit  30 . This means, as viewed from another perspective, that each fan  32  draws air SA from the outlet  27   b  of the branch pipe  27 . Each fan  32  can change the static pressure in each fan unit  30  (in front of the inlet  181   a  of the ventilation path  181 ) by changing the rotation speed. Assuming that the static pressure of the duct  20  is constant, each fan  32  can increase the static pressure in each fan unit  30  (in front of the inlet  181   a  of the ventilation path  181 ) by increasing the rotation speed. Increase in the static pressure in the fan unit  30  increases the amount of air SA flowing through the ventilation path  181 . This change in amount of air flowing as described above changes supply air volume blown into the air conditioned space TS from the outlet  181   b  of each ventilation path  181 . 
     The controller  400  includes the main controller  40  and the plurality of fan controllers  34 . The main controller  40  and the plurality of fan controllers  34  are connected to one another to constitute the controller  400 . The main controller  40  controls the rotation speed of the blower  29 . In other words, the main controller  40  controls the output of the blower  29 . If the output of the blower  29  increases, the state of the blower  29  changes so that amount of air blowing of the blower  29  increases. 
     One fan controller  34  is provided for each fan unit  30 . Each fan controller  34  gives a command concerning change in air flow volume to the corresponding fan  32 . Each fan controller  34  stores target air flow volume. Each fan controller  34  gives a command (command value of air flow volume) to increase the rotation speed of the fan  32  if the supply air volume is insufficient for the target air flow volume. Conversely, the fan controller  34  gives a command (command value of air flow volume) to reduce the rotation speed of the fan  32  if the supply air volume is excessive compared to the target air flow volume. 
     The controller  400  obtains information on the amount of air supplied to the air conditioned space TS from the plurality of fans  32 . The information on the amount of air is, for example, the amount of air to be supplied to the air conditioned space TS per second, and the amount of air to be supplied is, in other words, necessary supply air volume. The required output of the blower  29  is determined on the basis of the obtained information on the amount of air. The controller  400  controls the output of the blower  29  to achieve the required output thus determined. Specifically, each fan controller  34  obtains information on the amount of air of the fan unit  30  from the corresponding fan unit  30 . Each fan controller  34  outputs the information on the amount of air to the main controller  40 . 
     (5) Detailed Configuration 
     (5-1) Heat Exchanger Unit  10   
     The heat exchanger unit  10  includes, in addition to the blower  29  described above, the use side heat exchanger  11 , a use side air flow volume detection sensor  23 , a use side air temperature sensor  24 , and a water volume adjustment valve  25 . The use side heat exchanger  11  is supplied with, for example, cold water or hot water as a heating medium from the heat source unit  50 . The heating medium supplied to the use side heat exchanger  11  may be materials other than cold water or hot water, may be brine for example. The use side air flow volume detection sensor  23  may be, for example, an air flow volume sensor, a wind speed sensor, or a differential pressure sensor. 
     The use side air flow volume detection sensor  23  detects air flow volume of air sent out by the blower  29 . The use side air flow volume detection sensor  23  is connected to the main controller  40 . The value of the air flow volume detected by the use side air flow volume detection sensor  23  is sent from the use side air flow volume detection sensor  23  to the main controller  40 . The air flow volume detected by the use side air flow volume detection sensor  23  is air flow volume of air flowing through the main pipe  26  of the duct  20 . In other words, the air flow volume detected by the use side air flow volume detection sensor  23  is a total of supply air volume of air supplied from the plurality of fan units  30  to the air conditioned space TS. 
     The use side air temperature sensor  24  detects the temperature of the air SA sent from the blower  29  to the duct  20 . The use side air temperature sensor  24  is connected to the main controller  40 . The value of the temperature detected by the use side air temperature sensor  24  is sent from the use side air temperature sensor  24  to the main controller  40 . 
     The heat exchanger unit  10  is connected through a ventilation path  182  to the air conditioned space TS. Air RA that has returned through the ventilation path  182  from the air conditioned space TS is sent out by the blower  29  to the duct  20  through the use side heat exchanger  11 . When passing through the use side heat exchanger  11 , the air RA exchanges heat with the cold water or the hot water flowing through the use side heat exchanger  11  to become conditioned air. The water volume adjustment valve  25  adjusts the amount of heat given to the air SA that has been subjected to the heat exchange in the use side heat exchanger  11  to be sent to the duct  20 . The opening degree of the water volume adjustment valve  25  is controlled by the main controller  40 . As the opening degree of the water volume adjustment valve  25  is increased, the amount of water flowing through the use side heat exchanger  11  increases, so that the amount of heat exchanged between the use side heat exchanger  11  and the air SA per unit time increases. Conversely, as the opening degree of the water volume adjustment valve  25  is reduced, the amount of water flowing through the use side heat exchanger  11  decreases, so that the amount of heat exchanged between the use side heat exchanger  11  and the air SA per unit time decreases. 
     (5-2) Fan Unit  30   
     As with the first embodiment, the fan unit  30  includes, in addition to the fan  32  described above, the unit casing  31  and the air flow volume detection unit  33 . Since the configurations of the unit casing  31 , the fan  32 , and the air flow volume detection unit  33  of the fan unit  30  are similar to those of the first embodiment, the detailed description is omitted. The fan unit  30  is one product in which the fan  32  and the air flow volume detection unit  33  are attached to the unit casing  31 . The air flow volume detection unit  33  detects the air flow volume of air sent out by the fan  32  or equivalent air flow volume that is a physical quantity corresponding to the air flow volume. Each air flow volume detection unit  33  is connected to one corresponding fan controller  34 . The value of the air flow volume or the equivalent air flow volume detected by the air flow volume detection unit  33  is sent to the fan controller  34 . The air flow volume or the equivalent air flow volume detected by the air flow volume detection unit  33  is the air flow volume of air flowing through the ventilation path  181 . In other words, the air flow volume or the equivalent air flow volume detected by the air flow volume detection unit  33  is supply air volume of air supplied from each fan unit  30  to the air conditioned space TS. The air flow volume detection unit  33  may be, for example, an air flow volume sensor, a wind speed sensor, or a differential pressure sensor. The value detected by the air flow volume sensor is the value of the air flow volume, and the value of the wind speed detected by the wind speed sensor or the value of the differential pressure detected by the differential pressure sensor is the value of the equivalent air flow volume. 
     (5-3) Remote Sensor  170   
     A plurality of remote sensors  170  has a function of a temperature sensor. Each remote sensor  170  is configured to send data indicating the temperature of the air conditioned space TS to the corresponding fan controller  34 . 
     (6) Operation of Air Treatment System  1   
     Each of the plurality of fan controllers  34  receives a value of the detected temperature of a target space from the remote sensor  170  connected thereto. Each fan controller  34  holds data indicating a set temperature. For example, data indicating a set temperature is sent in advance from a remote controller (not shown) or the like to each fan controller  34 . Each fan controller  34  stores the data indicating a set temperature received from the remote controller or the like in a storage device  34   b  (see  FIG. 7 ) such as a built-in memory. Each fan controller  34  sends a value of the set temperature to the main controller  40 . The main controller  40  determines a target air flow volume of each fan unit  30  according to the temperature detected by the corresponding remote sensor  170  on the basis of the set temperature. The main controller  40  sends a value of the target air flow volume (command value of air flow volume) to each fan controller  34 . 
     The main controller  40  determines the output of the blower  29  according to a total amount of the target air flow volume to be supplied to the air conditioned space TS. 
     For example, when a comparison is made between a case where the static pressure at the outlet  26   b  of the main pipe  26  (the inlet  27   a  of the branch pipe  27 ) takes an intermediate value between the static pressure at the inlet  26   a  of the main pipe  26  and the static pressure at the outlet  27   b  of the branch pipe  27  and a case where the static pressure at the outlet  26   b  of the main pipe  26  takes a value greater than the intermediate value, the ratio of the output of the blower  29  is greater than the ratio of the output of the plurality of fans  32  in the case where the static pressure at the outlet  26   b  of the main pipe  26  takes a value greater than the intermediate value. Conversely, when a comparison is made between the case where the static pressure at the outlet  26   b  of the main pipe  26  (the inlet  27   a  of the branch pipe  27 ) takes the intermediate value and a case where the static pressure at the outlet  26   b  of the main pipe  26  takes a value smaller than the intermediate value, the ratio of the output of the blower  29  is smaller than the ratio of the output of the plurality of fans  32  in the case where the static pressure at the outlet  26   b  of the main pipe  26  takes a value smaller than the intermediate value. There is an efficient range for the ratio of the output of the blower  29  to the output of the plurality of fans  32 . The main controller  40  thus determines the output of the blower  29  so as to achieve an efficient ratio. In other words, it means that the main controller  40  determines the output of the blower  29  to a predetermined appropriate output for the total target air flow volume. 
     For example, considering the following method of determining the output of the blower  29 , it can be seen that the output of the blower  29  has a range of the output of the blower  29  that is suitable for reducing the power consumption. If the output of the blower  29  is increased and the total power consumption of the blower  29  and the plurality of fans  32  rises, the output of the blower  29  is gradually reduced, and if the total power consumption of the blower  29  and the plurality of fans  32  is determined to be the output of the blower  29  before starting to rise again, the range of the output thus determined is a range in which the power consumption is smaller than the other ranges. Conversely, if the output of the blower  29  is reduced and the total power consumption of the blower  29  and the plurality of fans  32  rises, the output of the blower  29  is gradually increased, and if the total power consumption of the blower  29  and the plurality of fans  32  is determined to be the output of the blower  29  before starting to rise again, the range of the output thus determined is a range in which the power consumption is smaller than the other ranges. If the output of the blower  29  is increased and the total power consumption of the blower  29  and the plurality of fans  32  falls, the output of the blower  29  is gradually increased, and if the total power consumption of the blower  29  and the plurality of fans  32  is determined to be the output of the blower  29  before starting to rise again, the range of the output thus determined is a range in which the power consumption is smaller than the other ranges. Conversely, if the output of the blower  29  is reduced and the total power consumption of the blower  29  and the plurality of fans  32  falls, the output of the blower  29  is gradually reduced, and if the total power consumption of the blower  29  and the plurality of fans  32  is determined to be the output of the blower  29  before starting to rise again, the range of the output thus determined is a range in which the power consumption is smaller than the other ranges. However, determining the appropriate output of the blower  29  is not limited to such methods. 
     After the main controller  40  determines the target air flow volume and sends a value of the target air flow volume (command value of air flow volume) to each fan controller  34 , each fan unit  30  other than the fan unit  30  with the highest fan efficiency is subjected to adjustment to the rotation speed of the fan  32  by the corresponding fan controller  34 . The rotation speed of the plurality of fans  32  is adjusted independently of one another. At this time, the rotation speed of the fan  32  of the fan unit  30  with the highest fan efficiency is maximized in the determined output of the blower  29 . Here, the fan unit  30  with the highest fan efficiency is the fan unit  30  with the lowest energy consumption for a case where the static pressure at the inlet  27   a  of the branch pipe  27  is the same and the supply air volume supplied to the air conditioned space TS is the same. Further, the fan unit  30  with the lowest fan efficiency is the fan unit  30  with the highest energy consumption for a case where the static pressure at the inlet  27   a  of the branch pipe  27  is the same and the supply air volume supplied to the air conditioned space TS is the same. 
     Each fan controller  34  controls the rotation speed of each fan  32  so that the supply air volume matches the target air flow volume. The plurality of fan controllers  34  controls the rotation speed of the plurality of fans  32  independently of one another. Each fan controller  34  increases the rotation speed of each fan  32  if the air flow volume detected by the air flow volume detection unit  33  is smaller than the target air flow volume. Each fan controller  34  reduces the rotation speed of each fan  32  if the air flow volume detected by the air flow volume detection unit  33  is larger than the target air flow volume. If the rotation speed of the fan unit  30  with the highest fan efficiency decreases, the main controller  40  changes the output of the blower  29  to adjust the rotation speed of the fan unit  30  with the highest fan efficiency to the maximum. 
     In changing the air flow volume, when changing the operating state of at least one second fan among the plurality of fans  32  or the air flow volume of at least one fan  32  among the plurality of fans  32 , the main controller  40  gives priority to increasing the output of a fan with high fan efficiency or reducing the output of a fan with low fan efficiency among the blower  29  and the plurality of fans  32 . In other words, the main controller  40  determines the output of the blower  29  and the target air flow volume of the plurality of fan units  30  so as to increase the output of the fan with high fan efficiency among the blower  29  and the plurality of fans  32  in order to increase the supply air volume to the air conditioned space TS. 
     Conversely, the main controller  40  determines the output of the blower  29  and the target air flow volume of the plurality of fan units  30  so as to reduce the output of the fan with high fan efficiency among the blower  29  and the plurality of fans  32  in order to reduce the supply air volume to the air conditioned space TS. 
     However, the main controller  40  increases the output of the blower  29  if the air flow volume of the fan unit with the maximum fan efficiency among the plurality of fan units  30  does not reach the target air flow volume. At this time, the main controller  40  increases the output of the blower  29  and keeps the rotation speed of the fan  32  of the fan unit  30  with the maximum fan efficiency at the maximum. 
     (7) Characteristics 
     (7-1) 
     In the air treatment system  1  described above, each fan unit  30  receives only a command value of air flow volume, and the fan controller  34  as the control unit automatically controls the air flow volume of the fan unit  30  itself. For example, if the fan controller  34  is given only a command value of air flow volume from the outside of the fan unit  30 , e.g., the main controller  40 , the fan unit  30  can control the air flow volume in accordance with the command value. As a result, in a case where the temperature of the conditioned air changes, the room temperature changes, the set value changes, or the like, the fan controller  34  of the fan unit  30  can omit the control operation for appropriately determining the air flow volume or the like, so that the fan unit  30  can reduce the control load. 
     (7-2) 
     The fan controller  34 , which is a control unit of each fan unit  30 , controls the rotation speed of the fan  32  so that the air flow volume indicated in the detected value approaches the command value. Controlling the rotation speed of the fan  32  so that the air flow volume indicated in the detected value approaches the command value means, for example, increasing the rotation speed of the fan  32  if the detected value of the air flow volume detection unit  33  is lower than the command value, and conversely, reducing the rotation speed of the fan  32  if the detected value is higher than the command value. As described above, the fan unit  30  that controls the rotation speed of the fan  32  such that the air flow volume indicated in the detected value approaches the command value easily implements automatic control of the air flow volume in the fan unit  30 . 
     (7-3) 
     The fan  32  is a centrifugal fan, and the fan casing  39  is housed in the unit casing  31 . The air flow volume is easily detected in a space inside the unit casing  31  and outside the fan casing  39  of the centrifugal fan. Therefore, the centrifugal fan facilitates control on the basis of the command value and the detected value of the air flow volume. 
     (7-4) 
     The fan controller  34  of the fan unit  30  is associated with the remote controller  60 . A command value given to the fan controller  34  is determined on the basis of an input of the remote controller  60 . Determining on the basis of an input of the remote controller  60  means that the input of the remote controller  60  is, for example, a parameter of a command value. In the first embodiment, the description takes an example where the command value is determined on the basis of the set temperature inputted by the remote controller  60  and the room temperature. Thus, the air flow volume of the fan unit  30  can be appropriately changed in accordance with the input of the remote controller  60 . 
     (8) Modification to the First Embodiment 
     (8-1) Modification 1A 
     In the first embodiment, the description is given of the case where the duct  20  is directly connected to the heat exchanger unit  10 ; however, the duct  20  may be indirectly connected to the heat exchanger unit  10 . For example, a configuration is possible in which an attachment having a plurality of air outlets for connecting the duct  20  to the heat exchanger unit  10  is mounted between the duct  20  and the heat exchanger unit  10 . Preparing a plurality of types of attachments that is different in numbers of connectable ducts  20  makes it possible to change the number of ducts  20  connectable to the heat exchanger unit  10  of the same model. 
     (8-2) Modification 1B 
     In the first embodiment, the description is given of the case where one blower unit  70  is connected to one fan unit  30 ; however, a plurality of blower units  70  may be connected to one fan unit  30 . This means that a plurality of openings  71  may be provided in one fan unit  30 . In such a case, a plurality of remote controllers  60  may be connected to each fan unit  30 , for example, one remote controller  60  may be provided for each blower unit  70 . 
     (8-3) Modification 1C 
     In the first embodiment, the description is given of the case where a vent hole  79  is provided on the wall between the rooms RM 1  and RM 2  and only one suction port  81  is provided. However, the number of suction ports  81  is not limited to one, and may be plural. Further, for example, a plurality of suction ports  81  may be provided in the same room RM 1 , or may be provided in both different rooms RM 1  and RM 2 . In a case where the suction port  81  is provided in each of the rooms RM 1  and RM 2 , the vent hole  79  does not need to be provided. 
     (8-4) Modification 1D 
     The fan unit  30  connected to the other end  22  of the duct  20  with one end  21  connected to the heat exchanger unit  10  may be connected to yet another duct  20  and another fan unit  30 . For example, a plurality of fan units  30  may be connected in series to one distribution flow path. One example of such a connection configuration is to connect two ducts  20 , two fan units  30 , and one blower unit  70  in series in the order of the duct  20 , the fan unit  30 , the duct  20 , the fan unit  30 , and the blower unit  70  from the heat exchanger unit  10 . Providing a plurality of power sources in one distribution flow path makes it possible to set a distance between the heat exchanger unit  10  and the opening  71  to be longer than a case where only one identical power source is provided. 
     (8-5) Modification 1E 
     In the first embodiment, the description is given of the case where one heat exchanger unit  10  is connected to one heat source unit  50 ; however, the connection configuration between the heat source unit  50  and the heat exchanger unit  10  is not limited thereto. For example, a plurality of heat exchanger units  10  may be connected to one heat source unit  50 . Alternatively, a plurality of heat source units  50  may be connected to the plurality of heat exchanger units  10 . In these connection configurations, the heat exchanger unit  10  may be provided with a flow rate adjusting device for adjusting the flow rate of the refrigerant flowing through the use side heat exchanger  11 . An example of such a flow rate adjusting device is a flow rate adjusting valve capable of changing an opening degree. 
     (8-6) Modification 1F 
     In the first embodiment, the description is given of the case where the compressor  51  of the heat source unit  50  is of a type capable of changing the rotation speed. However, the compressor  51  of the heat source unit  50  may be of a type incapable of changing the rotation speed. 
     (8-7) Modification 1G 
     In the first embodiment, the description is given of the case where the air treatment system  1  is configured to switch between the cooling operation and the heating operation. However, the technical concept of the first embodiment is applicable to an air conditioning system for cooling or heating only. 
     (8-8) Modification 1H 
     In the first embodiment, the description is given of the case of the refrigeration cycle apparatus in which the heat source unit  50  and the heat exchanger unit  10  are connected to each other to flow the refrigerant through the use side heat exchanger  11 ; however, the heat source unit  50  is not limited to the configuration in which the heat exchanger unit  10  is connected to constitute the refrigeration cycle apparatus. The heat source unit that supplies heat energy to the use side heat exchanger  11  may be configured to supply a heating medium such as hot water and/or cold water. 
     In the configuration of flowing the heating medium through the use side heat exchanger  11  as described above, a flow rate adjusting device for adjusting the flow rate of the heating medium flowing through the use side heat exchanger  11  may be provided in the heat exchanger unit  10 . 
     Further, in a case where the heat exchanger unit  10  is connected to the heat source unit for suppling such a heating medium, a plurality of heat exchanger units  10  may be connected to one heat source unit. 
     (8-9) Modification 1I 
     In the first embodiment, the description is given of the case where, at startup, the main controller  40  requests the calculated total air flow volume of air passing through the use side heat exchanger  11  and a refrigerant circulation rate necessary for the refrigerant circuit  200  calculated on the basis of the calculated temperature of air sucked into the heat exchanger unit  10 . However, the method for determining the necessary refrigerant circulation rate requested by the main controller  40  is not limited to the method described above. 
     For example, the air treatment system  1  may be configured as follows. At startup, the main controller  40  calculates total air flow volume of air that passes through the use side heat exchanger  11  by summing the amount of air supplied from all the fan units  30 . The main controller  40  stores, in an internal memory, for example, an air flow volume table indicating a relationship between the total air flow volume and the necessary refrigerant circulation rate. The main controller  40  selects air flow volume closest to the calculated total air flow volume from among air flow volumes indicated in the air flow volume table. The main controller  40  requests the heat source controller  56  to supply a refrigerant circulation rate corresponding to the total air flow volume selected in the air flow volume table. The air treatment system  1  may be configured such that the main controller  40  gives, to the fan controller  34 , a command (command value of air flow volume) to cause the plurality of fan units  30  to change the amount of air supplied corresponding to the difference (command value of air flow volume) between the air flow volume selected in the air flow volume table and the total air flow volume. 
     Further, for example, the air treatment system  1  may be configured as follows. At startup, the main controller  40  receives a set temperature of the remote controller  60  through the fan controller  34 . Further, the main controller  40  receives an indoor air temperature detected by the remote controller  60 , an indoor air temperature calculated on the basis of a detected value of the suction temperature sensor  101 , or an indoor air temperature from an indoor temperature sensor capable of sending an indoor air temperature to the main controller  40 . The main controller  40  calculates the entire air conditioning load of the air treatment system  1  on the basis of the received set temperature and indoor air temperature. The main controller  40  calculates total air flow volume and a necessary refrigerant circulation rate on the basis of the calculated air conditioning load. The main controller  40  calculates an amount of air supplied by each fan unit  30  on the basis of a product of the total air flow volume and the ratio of the air conditioning load of each fan unit  30 , and gives a command (command value of air flow volume) to the plurality of fan controllers  34 . The air treatment system  1  may be so configured that each fan controller  34  makes its own adjustment according to the amount of air supplied instructed by the main controller  40 . 
     (8-10) Modification 1J 
     In the first embodiment, the description is given of the case where the main controller  40  of the air treatment system  1  mainly determines total air flow volume and performs control so as to follow the conditions related to the refrigerant of the heat source unit  50  to the total air flow volume. However, the air treatment system  1  may be so configured that, conversely, the conditions related to the refrigerant of the heat source unit  50  are mainly determined and the total air flow volume is determined so as to follow the conditions. 
     For example, the air treatment system  1  is so configured that the heat source controller  56  controls an operating frequency of the compressor  51  and/or an opening degree of the expansion valve  53 . In the air treatment system  1  configured as described above, the heat source controller  56  keeps track of information on the total air flow volume of air currently passing through the use side heat exchanger  11 . The heat source controller  56  informs the main controller  40  that the air flow volume needs to be increased or decreased with respect to the current total air flow volume on the basis of the information on the operating frequency of the compressor  51  and/or the valve opening degree of the expansion valve  53 . The main controller  40  receives a command to increase or decrease the air flow volume from the heat source controller  56 , calculates at what rate is appropriate to increase or decrease the air flow volume of each fan unit  30  in order to control the energy of the entire system, and gives a command (command value of air flow volume) to the plurality of fan units  30 . 
     (8-11) Modification 1K 
     In the air treatment system  1  of the first embodiment, a refrigerant circulation rate in the refrigerant circuit  200  is adjusted by changing an operating frequency of the compressor  51 . Controlling the refrigerant circulation rate in the air treatment system  1  is, however, not limited to the control over the operating frequency of the compressor  51 . For example, the control is possible in such a manner that the refrigerant circulation rate of the refrigerant circuit  200  is adjusted by adjusting a valve opening degree of the expansion valve  53  together with the operating frequency of the compressor  51  or by adjusting the opening degree of the expansion valve  53 . 
     (8-12) Modification 1L 
     The operation of the air treatment system  1  may be controlled as follows. In the air treatment system  1 , set air flow volume inputted from the plurality of remote controllers  60  is a basic amount of air supplied based on which the amount of air supplied by the plurality of fan units  30  is determined. However, if the set air flow volume is not changed, after the set temperature is reached, the temperature falls below the set temperature in the cooling operation and exceeds the set temperature in the heating operation. To address this, in order to converge the indoor air temperature on the set temperature, the amount of air supplied by each fan unit  30  is changed from the set air flow volume in response to a command (command value of air flow volume) from the main controller  40 . The main controller  40  calculates an air conditioning load on the basis of the temperature difference between the indoor air temperature and the set temperature, and determines a necessary amount of air supplied on the basis of the air conditioning load and the blowing temperature of each fan unit  30 . For example, since the air conditioning load is 0 (zero) for the case where the indoor air temperature matches the set temperature and there is no temperature difference, the main controller  40  stops blowing air for the fan unit  30  whose indoor air temperature matches the set temperature, even if the set air flow volume is not 0 (zero). However, in order to prevent air from flowing backward from the opening  71  toward the heat exchanger unit  10 , even the fan unit  30 , which is to be stopped if judged on the basis of the air conditioning load, may be so controlled that the amount of air supplied is not set to 0 (zero) in order to control the backflow. 
     (8-12-1) At Startup 
     The fan controllers  34  of the fan units  30   a  to  30   d  each send, to the main controller  40 , the amount of air supplied by the fan units  30   a  to  30   d  from the set air flow volume of the four remote controllers  60 . Note that the air treatment system  1  may be so configured that, when even the stopped fan unit  30  is in operation of extremely slightly sending air in order to prevent air from flowing backward from the opening  71  toward the heat exchanger unit  10 , the minute amount of air supplied is also included in the total air flow volume. Alternatively, the air treatment system  1  may be so configured that the minute amount of air supplied is not included in the total air flow volume. 
     The main controller  40  calculates total air flow volume of air passing through the use side heat exchanger  11  by summing the amount of air supplied from all the fan units  30 . The main controller  40  calculates an air temperature of air sucked into the heat exchanger unit  10  from the suction temperature sensor  101  of the heat exchanger unit  10 . The main controller  40  then requests, from the heat source controller  56  of the heat source unit  50 , a necessary refrigerant circulation rate calculated on the basis of the total air flow volume of air passing through the use side heat exchanger  11  and the air temperature. The heat source controller  56  of the heat source unit  50  changes the refrigerant circulation rate by changing the operating frequency of the compressor  51  in response to the request from the main controller  40 . 
     (8-12-2) During Normal Operation 
     In the normal operation, the air treatment system  1  changes the control between a case where the total air flow volume is equal to or greater than a lower limit value and a case where the total air flow volume is smaller than the lower limit value. 
     (8-12-2-1) Case where Total Air Flow Volume is Equal to or Greater than Lower Limit Value 
     When a predetermined time has passed since the startup and the system is in normal operation, the main controller  40  determines whether or not the total air flow volume is equal to or greater than the lower limit value. Setting of the lower limit value is described later. If the total air flow volume is equal to or larger than the lower limit value, the main controller  40  controls the air treatment system  1  in the following steps. 
     When a predetermined time has passed since the startup and the system is in normal operation, each fan controller  34  is configured to recalculate an amount of air supplied at a predetermined interval. In the recalculation, for example, the indoor air temperature detected by the remote controller  60  is used to calculate the air conditioning load on the basis of a situation where the indoor air temperature in the vicinity of each blower unit  70  is “close to” or “far from” the set temperature, and each fan controller  34  corrects the set air flow volume. Then, the corrected amount of air supplied corrected by each fan unit  30  is sent to the main controller  40 . Note that another configuration is possible in which the main controller  40  makes the calculation related to the correction to the set air flow volume. The main controller  40  recalculates the amount of air supplied, which is sent from the plurality of fan controllers  34  for each interval, to calculate total air flow volume, and if the total air flow volume is equal to or greater than the lower limit value, the main controller  40  requests the heat source controller  56  of the heat source unit  50  to send a necessary refrigerant circulation rate calculated on the basis of the total air flow volume of the air passing through the use side heat exchanger  11  and the air temperature thereof for each interval. The heat source controller  56  of the heat source unit  50  changes the refrigerant circulation rate by changing the operating frequency of the compressor  51  in response to the request from the main controller  40 . 
     (8-12-2-2) Case where Total Air Flow Volume is Smaller than Lower Limit Value 
     In a case where the total air flow volume is smaller than the lower limit value, the main controller  40  calculates a shortage which is a difference between the calculated total air flow volume and the lower limit value. The main controller  40  allocates the shortage to the plurality of fan units  30  according to a predetermined air flow volume distribution rule. In a case where the shortage is allocated to the plurality of fan units  30 , since if suffices if the total air flow volume is equal to or greater than the lower limit value, there are two cases: one is to allocate an amount of air supplied that matches the shortage and the other is to allocate an amount of air supplied that exceeds the shortage. 
     For example, a case where the lower limit value is 30 m 3 /min, the fan controller  34  of the fan unit  30   a  requests 16 m 3 /min, the fan controller  34  of the fan unit  30   b  requests 0 m 3 /min, the fan controller  34  of the fan unit  30   c  requests 10 m 3 /min, and the fan controller  34  of the fan unit  30   d  requests 6 m 3 /min to the main controller  40  is considered. At this time, the total air flow volume calculated by the main controller  40  is 32 m 3 /min&gt;30 m 3 /min, and the main controller  40  determines that the total air flow volume is greater than the lower limit value. 
     Next, in response to the fan controller  34  of the fan unit  30   c  receiving a command to stop sending air from the remote controller  60 , the request of the fan controller  34  of the fan unit  30   c  is changed from 10 m 3 /min to 0 m 3 /min. Then, since the total air flow volume reduces from 32 m 3 /min to 22 m 3 /min, the main controller  40  determines that a command to change the total air flow volume to be equal to or smaller than the lower limit value is given. 
     As an example, when determining that a command to change the total air volume to be equal to or smaller than the lower limit value is given, the main controller  40  evenly allocates the shortage to, for example, the operating fan units  30 . In the above case, 8 (=30−22) m 3 /min is allocated to the fan unit  30   a  at 4 m 3 /min and to the fan unit  30   b  at 4 m 3 /min, which changes to 20 m 3 /min for the fan unit  30   a  and 10 m 3 /min for the fan unit  30   d.    
     As another example, when determining that a command to change the total air volume to be equal to or smaller than the lower limit value is given, the main controller  40  evenly allocates the shortage to, for example, all the fan units  30 . In the above case, 8 (=30−22) m 3 /min is allocated to the fan units  30   a  to  30   d  by 2 m 3 /min, which changes to 18 m 3 /min for the fan unit  30   a,  2 m 3 /min for the fan unit  30   b,  2 m 3 /min for the fan unit  30   b , and 8 m 3 /min for the fan unit  30   d.    
     (8-12-2-3) Setting of Lower Limit Value 
     The main controller  40  determines a lower limit value of the total air flow volume of the air treatment system  1  on the basis of, for example, a heat exchanger temperature. For example, in a case where the heat exchanger temperature is high during the cooling operation, the main controller  40  determines that the heat source unit  50  does not have enough capacity to supply heat energy, and sets the lower limit value of the total air flow volume at a high value. In comparison with such a case, in a case where the heat exchanger temperature is low during the cooling operation, the main controller  40  determines that there is room for the heat source unit  50  to supply heat energy, and sets the lower limit value of the total air flow volume at a value lower than that in the above-described case. The specific value of the lower limit value is determined by, for example, a test and/or simulation of an actual machine of the air treatment system  1 . 
     (8-12-2-4) Detection of Air Backflow 
     For example, in the distribution flow path including the duct  20   a , the fan unit  30   a , and the blower unit  70   a , airflow from the heat exchanger unit  10  toward the opening  71  is normal airflow, and conversely, airflow from the opening  71  toward the heat exchanger unit  10  is abnormal airflow and is air backflow. Similarly, in the distribution flow path including the ducts  20   b  to  20   d , the fan units  30   b  to  30   d , and the blower units  70   b  to  70   d , airflow from the opening  71  toward the heat exchanger unit  10  is air backflow. The air flow volume detection unit  33  provided for each of the fan units  30   a  to  30   d  sends the detection result to the main controller  40  through the fan controller  34 . 
     The main controller  40  determines that airflow is normal if the air pressure at the outlet  37  is lower or equal to the air pressure at the inlet  36  of the fan units  30   a  to  30   d , and conversely, the main controller  40  determines that air backflow is occurring if the air pressure at the outlet  37  is higher than the air pressure at the inlet  36  of the fan units  30   a  to  30   d.    
     (8-12-2-5) Operation when Air Backflow Occurs 
     The main controller  40  eliminates air backflow by operating together with the fan unit  30 . Specifically, the main controller  40  detects the fan unit  30  that is connected to the distribution flow path where the air backflow is occurring. The main controller  40  sends a command (command value of air flow volume) to increase the rotation speed of the fan motor  38  to the fan controller  34  of the fan unit  30  in the distribution flow path where the air backflow is occurring. For example, in a case where the fan motor  38  stops, a command (command value of air flow volume) to start driving at a predetermined rotation speed is sent. For example, in a case where the fan motor  38  rotates at a low speed, a command to further increase the rotation speed of the fan motor  38  (command value of air flow volume) is sent. 
     Note that the air deflector  74  may be used to eliminate the air backflow, provided the air deflector  74  can change the air resistance. For example, a configuration is possible in which the air deflector  74  of the blower unit  70  where the air backflow is occurring is fully closed in a case where the fan motor  38  stops. Another configuration is possible in which, in a case where the fan motor  38  rotates at a low speed, a command (command value of air flow volume) to further increase the rotation speed of the fan motor  38  and increase the air resistance of the air deflector  74  is sent. 
     Another configuration may be used in which a backflow prevention damper that is fully closed only by the force of the air backflow is provided in the distribution flow path. In such a case, the backflow can be prevented even without a command from the main controller  40 . 
     (8-12-3) Another Control Method 
     In the control method described above, the lower limit value of the total air flow volume is determined on the basis of the heat exchanger temperature of the use side heat exchanger  11 ; however, the condensation temperature (TC), the evaporation temperature (TE), the degree of superheating (SH), and the degree of subcooling (SC) may be used to determine the lower limit value of the total air flow volume. The degree of superheating can be calculated by using, for example, the inlet temperature and the outlet temperature of the use side heat exchanger  11 , or the inlet pressure and the outlet temperature of the use side heat exchanger  11 . The degree of subcooling can be calculated using, for example, the inlet temperature and the outlet temperature of the use side heat exchanger  11 , or the inlet pressure and the outlet temperature of the use side heat exchanger  11 . 
     The lower limit value of the total air flow volume may be, for example, a fixed value determined in advance, and if the lower limit value is determined to be 8 m 3 /min in advance, then the main controller  40  performs control so that the lower limit value does not fall below the lower limit value of 8 m 3 /min at any time. 
     The air treatment system  1  may be so configured that, in the cooling operation, the lower limit value of the total air flow volume is determined according to, for example, the degree of superheating, the current total air flow volume, and the suction temperature of the air sucked into the heat exchanger unit  10 . The air treatment system  1  may be so configured that, in the heating operation, the lower limit value of the total air flow volume is determined according to the degree of subcooling, the current total air flow volume, and the suction temperature of the air sucked into the heat exchanger unit  10 . Alternatively, the air treatment system  1  may be so configured that the lower limit value of the total air flow volume is determined according to the refrigerant circulation rate (operating frequency of the compressor  51 , for example), the evaporation temperature (TE), the temperature of the air sucked into the heat exchanger unit  10 , and the sucked air flow volume. The air treatment system  1  may be so configured that the lower limit value of the total air flow volume is determined according to the current air flow volume and the excess and deficiency of air flow volume calculated on the basis of the degree of dryness or the degree of wetness of the refrigerant after passing through the use side heat exchanger  11 . Further, the air treatment system  1  may be so configured that the lower limit value of the total air flow volume is determined according to the refrigerant pressure and the temperature of the refrigerant. at the outlet of the use side heat exchanger  11   
     (8-13) Modification 1M 
     (8-13-1) 
     In the modification L, the description provides an example of the fan motor  38  capable of changing the rotation speed as a plurality of actuators configured to change individual amounts of air supplied of conditioned air sucked from the heat exchanger unit  10  through the plurality of ducts  20  and supplied to the plurality of openings  71  of the air conditioned space TS. However, the actuator is not limited to the fan motor  38 , and for example, a driving motor (not shown) of a damper may be used as the plurality of actuators. The fan motor  38  of the fan  32  shown in  FIG. 5  may be a motor of a type capable of changing the rotation speed similar to that of the first embodiment, or may be a motor of a type incapable of changing the rotation speed. In a case where the fan motor  38  is the motor of a type incapable of changing the rotation speed, the amount of air supplied (air flow volume) from the fan unit  30  to the blower unit  70  is changed only by the damper. On the other hand, in a case where the fan motor  38  is the motor of a type capable of changing the rotation speed, the amount of air supplied (air flow volume) from the fan unit  30  to the blower unit  70  is changed not only with change in the opening degree of the damper but with change in the rotation speed of the fan motor  38 . 
     Further, as a unit for changing individual amounts of air supplied of conditioned air to be supplied to the opening  71 , a damper unit with a damper but no fan can be used. In other words, the air treatment system  1  can be so configured as to include, for example, a fan unit that only rotates the fan at a constant speed and does not have a function to change the amount of air supplied, and a damper unit separate from the fan unit. For example, the air treatment system  1  may be so configured that a damper unit capable of changing the amount of air supplied with a damper is provided in a part of at least one of the ducts  20   a  to  20   d . Alternatively, the air treatment system  1  may be so configured that the fan unit  30  having a function to change the amount of air supplied and the damper unit having a function to change the amount of air supplied are disposed together in at least one of the ducts  20   a  to  20   d.    
     (8-13-2) Operation when Backflow Occurs 
     The main controller  40  eliminates air backflow by operating together with the fan unit  30 . In order to eliminate the air backflow, first, the main controller  40  detects the fan unit  30  that is connected to the distribution flow path where the air backflow is occurring. In a case where the fan unit  30  is configured to adjust the amount of air supplied only with the damper, the main controller  40  sends a command to change the opening degree of the damper to the fan controller  34  of the fan unit  30  in the distribution flow path where the air backflow is occurring. For example, in a case where the fan unit  30  where the air backflow is occurring is not operated, a command to fully close the damper is sent. Since air backflow does not normally occur when the fan motor  38  sends air at a constant rotation with the opening degree of the damper, the main controller  40  notifies the user of the occurrence of an abnormality, for example, with the remote controller  60  if the air backflow occurs in such a case. 
     In a case where the fan unit  30  is configured to adjust the amount of air supplied with both the rotation speed of the fan motor  38  and the opening degree of the damper, the main controller  40  sends a command to change the rotation speed of the fan motor  38  and/or the opening degree of the damper to the fan controller  34  of the fan unit  30  in the distribution flow path where the air backflow is occurring. For example, in a case where the fan unit  30  where the air backflow is occurring is not operated, a command to fully close the damper is sent. For example, in a case where the fan motor  38  rotates at a low speed, a command to further increase the rotation speed (command value of air flow volume) is sent. Another configuration is possible in which, for example, in a case where the fan motor  38  rotates at a low speed, a command (command value of air flow volume) to reduce the opening degree of the damper and increase the rotation speed of the fan motor  38  is sent. 
     (8-14) Modification 1N 
     In the first embodiment, the description provides the case where the air flow volume detection unit  33  is used as the detection device for detecting air backflow; however, the detection device for detecting air backflow is not limited to the air flow volume detection unit  33 . Such a detection device may be a directional wind speed sensor. In a case where the directional wind speed sensor is used instead of the air flow volume detection unit  33 , the wind speed sensor is disposed in, for example, the fan unit  30  and connected to the fan controller  34 . In the case of using the directional wind speed sensor, for example, the main controller  40  can detect that air flows in a normal direction when the wind speed is in the positive direction, and that air backflow is occurring when the wind speed is in the negative direction opposite to the normal direction. In addition, the detection device can be configured using a plurality of non-directional wind speed sensors. The plurality of non-directional wind speed sensors detects the distribution of wind speed, and if the distribution of wind speed is distribution that occurs during backflow, then the main controller  40  can determine that the backflow is occurring. 
     (8-15) Modification 1O 
     In the first embodiment, the description is given of the case where the plurality of fan controllers  34  of the plurality of fan units  30  is directly connected in parallel to the main controller  40  installed in the heat exchanger unit  10 . However, the plurality of fan units  30  may be classified into a master unit and a slave unit, and the fan controller  34  may be connected to the main controller  40 . 
     For example, in a case where five fan units  30 M and  30 S are connected to one heat exchanger unit  10 , as shown in  FIG. 8 , the five fan units are classified into one fan unit  30 M as the master unit and the four fan units  30 S as the slave units. The five fan units  30 M and  30 S have the same configuration as that of the fan unit  30  described above. The main controller  40  of the heat exchanger unit  10  is connected to the heat source controller  56  of the heat source unit  50  and one fan unit  30 M as the master unit. Further, the fan controller  34  of the one fan unit  30 M as the master unit is connected to the fan controllers  34  of the four fan units  30 S as the slave units. The main controller  40  manages the fan controllers  34  of the four fan units  30 S as the slave units through the fan controller  34  of the fan unit  30 M as the master unit. The main controller  40  may directly give a command (command value of air flow volume) to the fan controllers  34  of the four slave units, or the fan controller  34  of the fan unit  30 M as the master unit may give a command in response to the command (command value of air flow volume) from the main controller  40 . 
     (8-16) Modification 1P 
     In the first embodiment and the modification 1O, the main controller  40  is installed in the heat exchanger unit  10 ; however, the main controller  40  may be installed in the fan unit  30 M as the master unit as shown in  FIG. 9 or 10 . 
     In such a case, the heat exchanger unit  10  is provided with a terminal  19  for connection to various sensors disposed therein. The main controller  40  is connected to a sensor inside the heat exchanger unit  10  through the terminal  19  of the heat exchanger unit  10 . As shown in  FIG. 9 , the heat source controller  56  of the heat source unit  50  is connected to the main controller  40  of the fan unit  30 M through the heat exchanger unit  10 . Alternatively, as shown in  FIG. 10 , the heat source controller  56  of the heat source unit  50  is directly connected to the main controller  40  of the fan unit  30 M. 
     For example, in a case where the five fan units  30 M,  30 GM, and  30 S are connected to one heat exchanger unit  10 , as shown in  FIG. 9 or 10 , the five fan units are classified into the one fan unit  30 M as the master unit, the two fan units  30 GM as group master units, and the two fan units  30 S as the slave units. Here, the fan controller  34  of the fan unit  30 M as the master unit is only replaced with the main controller  40 , and the configurations of the five fan units  30 M,  30 GM, and  30 S are the same as that of the fan unit  30  described above. The main controller  40  of the fan unit  30 M is connected to the fan units  30 GM as the group master units. Next, the fan controller  34  of the fan unit  30 GM as each of the group master units is connected to the fan controller  34  of the fan unit  30 S as the slave unit of each group. The description herein takes the case where the fan controller  34  of one fan unit  30 S as the slave unit is connected to the fan controller  34  of one fan unit  30 GM as the group master unit; however, the number of fan controllers  34  of the slave units connected to the fan controller  34  of the group master unit is not limited to one, and may be two or more. Further, the number of group master units is not limited to two, and may be one or three or more. Another configuration is possible in which a plurality of fan controllers  34  of the fan units  30 S as the slave units is connected in parallel to the main controller  40  of one fan unit  30 M. 
     The main controller  40  manages the fan controllers  34  of the two fan units  30 GM as the group master units. In addition, the main controller  40  manages the fan controllers  34  of the two fan units  30 S as the group slave units through the fan controllers  34  of the fan units  30 GM as the group master units. The main controller  40  may directly give a command (command value of air flow volume) to the fan controllers  34  of the two slave units, or the fan controller  34  of the group master unit may give a command in response to the command (command value of air flow volume) from the main controller  40 . 
     (8-17) Modification 1Q 
     In the first embodiment and the modifications 1O to 1P, the main controller  40  is installed in the heat exchanger unit  10 ; however, as shown in  FIG. 11, 12, 13 , or  14 , the main controller  40  may be installed in a place other than the heat exchanger unit  10 , the fan unit  30 , and the heat source unit  50 . 
     In such a case, the heat exchanger unit  10  is provided with a terminal  19  for connection to various sensors disposed therein. The main controller  40  is connected to a sensor inside the heat exchanger unit  10  through the terminal  19  of the heat exchanger unit  10 . 
       FIG. 11  is a block diagram showing a configuration in which the main controller  40 , the fan controller  34 , and the heat source controller  56  are connected in a manner similar to those in the first embodiment, and the installation position of the main controller  40  is changed from the heat exchanger unit  10  in the first embodiment to another place. 
       FIG. 12  is a block diagram showing a configuration in which the main controller  40 , the fan controller  34 , and the heat source controller  56  are connected in a manner similar to those in the modification 1O shown in  FIG. 9 , and the installation position of the main controller  40  is changed from the heat exchanger unit  10  in the modification 1O to another place. 
     (8-18) Modification 1R 
     In the modification 1Q, the description takes the case where the plurality of fan controllers  34  of the plurality of fan units  30  is directly connected in parallel to the main controller  40  (see  FIG. 11 ) and the case where the fan controllers  34  of the two fan units  30 GM as the group master units are connected to the fan controller  34  of the one fan unit  30 M as the master unit and the fan controller  34  of the fan unit  30 S as the slave unit is connected to the group master unit (see  FIGS. 12 and 13 ). However, instead of providing the entire master unit, the master units may be classified into group master units and the fan controller  34  may be connected to the main controller  40 . 
     For example, in a case where the five fan units  30 GM and  30 S are connected to one heat exchanger unit  10 , as shown in  FIG. 14 , the five fan units are classified into the three fan units  30 GM as the group master units and the two fan units  30 S as the slave units. The five fan units  30 GM and  30 S have the same configuration as that of the fan unit  30  described above. The main controller  40  of the heat exchanger unit  10  is connected to the heat source controller  56  of the heat source unit  50  and the three fan units  30 GM as the group master units. Next, the fan controllers  34  of the two fan units  30 GM as the group master units are connected to the fan controller  34  of the fan unit  30 S as the slave unit of each group. However, the fan controller  34  as the slave unit is not connected to the fan controller  34  of the one fan unit  30 GM as the group master unit. The description herein takes the case where the fan controller  34  of one fan unit  30 S as the slave unit is connected to the fan controller  34  of one fan unit  30 GM as the group master unit and the case where the fan controller  34  of the slave unit is connected to the fan controller  34  of the one fan unit  30 GM as the group master unit; however, the number of fan controllers  34  of the slave units connected to the fan controller  34  of the group master unit is not limited to one, and may be two or more. 
     The main controller  40  manages the fan controllers  34  of the two fan units  30 S as the group slave units through the fan controllers  34  of the two fan units  30 GM as the group master units. The main controller  40  may directly give a command (command value of air flow volume) to the fan controllers  34  of the two slave units, or the fan controller  34  of the group master unit may give a command in response to the command (command value of air flow volume) from the main controller  40 . 
     As described above, since the main controller  40  is disposed in a place other than the heat exchanger unit  10  and the plurality of fan units  30 , the installation of the main controller  40  is no longer limited to the heat exchanger unit  10  and the plurality of fan units  30 GM and  30 S, which increases the flexibility of the installation of the main controller  40  and makes it easy to handle the main controller  40 . 
     (8-19) Modification 1S 
     For example, a configuration is possible in which the main controller  40  or the fan controller  34  calculates air flow volume by using the operating current of the fan  32  on the basis of the workload of the fan motor  38 . In such a case, a device that detects the operating current serves as the air flow volume detection unit. 
     (8-20) Modification 1T 
     In the first embodiment, the description takes the case where the main controller  40  calculates a refrigerant circulation rate, sends a request for changing the operating frequency of the compressor  51  to the heat source controller  56 , and the heat source controller  56  controls the operating frequency of the compressor  51 . However, the air treatment system  1  may be so configured that the main controller  40  controls the operating frequency of the compressor  51  and/or the opening degree of the expansion valve  53 . 
     (8-21) Modification 1U 
     In the first embodiment, the description takes the case where the plurality of ducts  20   a  to  20   d  is connected to the heat exchanger unit  10 , and the ducts  20   a  to  20   d  extend from the heat exchanger unit  10  to the fan units  30  without branching off on the way. However, a duct branching off on the way may be used in the air treatment system  1 . For example, the air treatment system  1  may be so configured that one fan unit  30  is connected to each branch of one duct, respectively. 
     (8-22) Modification 1V 
     In the first embodiment, the description takes the case where the heat exchanger unit  10 , which is an air treatment unit, does not have a blower for sending, to the duct  20 , the conditioned air that has been subjected to heat exchange by the use side heat exchanger  11 . However, the air treatment unit may include a blower for sending the conditioned air to the duct  20  to which the fan unit  30  is connected. 
     (9) Additional Description of the Modifications and the First Embodiment 
     (9-1) 
     The air treatment system  1  of the first embodiment includes the controller  400 , the plurality of ducts  20 ,  20   a  to  20   e , and the plurality of fan units  30 ,  30   a  to  30   d ,  30 M,  30 GM, and  30 S. The plurality of ducts  20 ,  20   a  to  20  serves to distribute the conditioned air that has passed through the use side heat exchanger  11  of the heat exchanger unit  10 . The plurality of fan units  30 ,  30   a  to  30   d ,  30 M,  30 GM, and  30 S is provided so as to correspond to the plurality of ducts  20 ,  20   a  to  20   e , and supply the conditioned air from the heat exchanger unit  10  through the plurality of ducts  20 ,  20   a  to  20   e  to the air conditioned space TS. The plurality of actuators is configured to change the amount of conditioned air supplied to the air conditioned space TS. In the first embodiment, the plurality of actuators is selected from among the plurality of fan motors  38 , the plurality of driving motors, and the plurality of air deflector motors  75 . The plurality of actuators is the plurality of fan motors  38 , the plurality of driving motors, or the plurality of air deflector motors  75  in some cases. In addition, the plurality of actuators may include different types of actuators, for example, both the fan motor  38  and the driving motor at the same time. Each of the plurality of ducts  20 ,  20   a  to  20   e  is disposed in one of the plurality of distribution flow paths. Each of the plurality of fan units  30 ,  30   a  to  30   d ,  30 M,  30 GM, and  30 S includes the fans  32 ,  32   a  to  32   d , which are first fans, and is arranged in one of the plurality of distribution flow paths. Each of the plurality of actuators is disposed in one of the plurality of distribution flow paths. The controller  400  controls the plurality of actuators to control the amounts of air supplied of the plurality of fan units  30 ,  30   a  to  30   d ,  30 M,  30 GM, and  30 S. As a result, the air treatment system  1  of the first embodiment can adjust the volume of air passing through the use side heat exchanger  11  for efficient heat exchange in the use side heat exchanger  11 , leading to the reduction in energy consumption. 
     (9-2) 
     The main controller  40  of the controller  400  of the first embodiment gives a plurality of commands concerning the amount of air supplied by the plurality of fan units  30  in order to control the rotation speed of the plurality of fan motors  38  which is a plurality of actuators of the plurality of fan units  30 , the driving motors of the plurality of dampers, or the air deflector motor  75  of the air deflector  74 . This enables adjustment to the volume of air passing through the use side heat exchanger  11  for efficient heat exchange in the use side heat exchanger  11 , leading to the reduction in energy consumption. 
     (9-3) 
     In the air treatment system  1  according to the first embodiment, since the main controller  40  is disposed in the heat exchanger unit  10 , it suffices if construct a network connecting the main controller  40  and the fan motors  38 , which are a plurality of actuators, in accordance with the flow of the conditioned air supplied from the heat exchanger unit  10 . Therefore, a network for sending a command from the main controller  40  can be easily constructed with the heat exchanger unit  10  as a starting point. 
     (9-4) 
     In a case where the main controller  40  is disposed in the fan unit  30 M as the master unit which is one of the plurality of fan units  30 , the air treatment system  1  including one main controller  40  in the plurality of fan units  30  can be formed by connecting the network of the plurality of fan units  30 , which facilitates the construction of the air treatment system  1 . In other words, since it is only required that at least one fan unit  30 M as the master unit is included in the plurality of fan units  30 , the air treatment system  1  can be easily designed and constructed. 
     Note that, in a case where a plurality of main controllers  40  is present, the plurality of main controllers  40  may be configured to cooperate and act like one main controller. For example, in a case where an extension is made, the newly added main controller  40  and the main controller  40  existing before the extension can be configured to communicate with each other to function as one new main controller. 
     (9-5) 
     In a case where the main controller  40  is disposed in a place other than the heat exchanger unit  10  and the plurality of fan units  30 , the installation of the main controller  40  is no longer limited to the heat exchanger unit  10  and the plurality of fan units  30 M,  30 GM and  30 S, which increases the flexibility of the installation of the main controller  40  and makes it easy to handle the main controller  40 . 
     (9-6) 
     The air treatment system  1  of the first embodiment is so configured that the airflow passing through the use side heat exchanger  11  is generated only by the air suction force of the plurality of fan units  30 . As a result, since the heat exchanger unit  10  does not need to include a power source for generating the airflow, the cost can be reduced as compared with the case where a power source for generating the airflow is provided in the heat exchanger unit  10 . In addition, the heat exchanger unit  10  can be easily made thinner, and the range in which the air treatment system  1  is installed can be expanded. 
     (9-7) 
     In a case where the heat exchanger unit  10  includes at least one of the gas pipe temperature sensor  102 , the liquid pipe temperature sensor  103 , and the use side heat exchanger temperature sensor  104  that are heat medium temperature sensors for detecting the temperature of the refrigerant that is a heating medium flowing through the use side heat exchanger  11  or the pipe connected to the use side heat exchanger  11 , and the suction temperature sensor  101  for detecting the temperature of the air sucked into the heat exchanger unit, and where the main controller  40  uses a detected value of at least one of the heat medium temperature sensor and the suction temperature sensor to determine a command concerning the increase or decrease in the amount of air supplied, the main controller  40  easily gives a command to supply, to the plurality of fan units  30 , air to meet the operating conditions of the heat exchanger unit  10 . For example, in a case where the heat energy supplied from the heat source unit  50  to the heat exchanger unit  10  is insufficient, the main controller  40  reduces the amount of air supplied on the basis of the detected value of the use side heat exchanger temperature sensor  104 , which reduces a problem such as excessive dropping of the temperature of the refrigerant supplied from the heat source unit  50 . 
     (9-8) 
     The remote controller  60  of the air treatment system  1  of the first embodiment has a set temperature function to set temperatures of the rooms RM 1  and RM 2  that are the air conditioned spaces TS and an indoor temperature detection function. The main controller  40  uses the set temperature of the remote controller  60  and the room temperature detected by the remote controller  60  to determine a command concerning the increase or decrease in the amount of air supplied. As a result, the main controller  40  can give a command to bring the temperature of the air conditioned space TS closer to the set temperature. In the first embodiment, the remote controller  60  is installed at a plurality of locations of the room RM 1  that is the air conditioned space TS, which makes it easy to bring the indoor air temperature at each of the plurality of locations closer to the set temperature. 
     (9-9) 
     The air treatment system  1  of the first embodiment includes the compressor  51  for compressing the refrigerant to be circulated in the use side heat exchanger  11 , the heat source side heat exchanger  52  for exchanging heat of the refrigerant circulated in the use side heat exchanger  11 , and the expansion valve  53  for expanding the refrigerant passing between the use side heat exchanger  11  and the heat source heat exchanger  52 . The main controller  40  is connected, through the heat source controller  56 , to the compressor  51  and/or the expansion valve  53  to control the system operation. As a result, it is possible to appropriately control the system operation by controlling the rotation speed of the compressor  51  and/or the opening degree of the expansion valve  53  so as to achieve a refrigerant circulation rate, for example, derived by calculation together with the increase or decrease in the amount of air supplied, and it is possible to control the increase or decrease in the amount of air supplied while causing the refrigerant circulating through the use side heat exchanger  11  and the heat source side heat exchanger  52  to perform an appropriate refrigeration cycle. 
     (9-10) 
     In the air treatment system  1  of the first embodiment, since the main controller  40  is connected to the compressor  51  and/or the expansion valve  53  for control over the system operation, the main controller  40  can appropriately control the system operation by controlling the rotation speed of the compressor  51  and/or the opening degree of the expansion valve  53  so as to, for example, achieve the refrigerant circulation rate derived by calculation with the increase or decrease in the amount of air supplied. The main controller  40  can control the increase or decrease in the amount of air supplied while causing the refrigerant circulating through the use side heat exchanger  11  and the heat source heat exchanger  52  to perform an appropriate refrigeration cycle. 
     (9-11) 
     In the air treatment system  1  of the first embodiment, the main controller  40  controls the fan motor  38  that is an actuator or the damper on the basis of information indicating the rotation speed of the compressor  51  and/or the opening degree of the expansion valve  53  for control over the system operation; therefore, it is possible to control the increase or decrease in the amount of air supplied while causing the refrigerant circulating through the use side heat exchanger and the heat source side heat exchanger to perform an appropriate refrigeration cycle. 
     (9-12) 
     The main controller  40  controls air flow volume of air passing through the use side heat exchanger  11  with the plurality of fan motors  38  while adjusting the fan motor  38  that is a plurality of actuators in order to prevent backflow, in the plurality of ducts  20 , of the conditioned air flowing from the heat exchanger unit  10  toward the plurality of openings  71 . As a result, it is possible to prevent reduction in heat exchange efficiency due to the backflow of the conditioned air in the plurality of ducts. Further, together with the control described above, the main controller  40  controls the circulation amount of the refrigerant by the rotation speed of the compressor  51  and/or the opening degree of the expansion valve  53 , which makes it easy to reduce the heat exchange efficiency deterioration. 
     (9-13) 
     The air treatment system  1  of the first embodiment includes each damper of each fan unit  30  attached to each duct  20 , and a driving motor (an example of the actuator) for driving each damper. The main controller  40  controls to adjust the opening degrees of the plurality of dampers in order to prevent backflow, in the plurality of ducts  20 , of the conditioned air flowing from the heat exchanger unit  10  toward the plurality of openings  71 . As a result, it is possible to easily prevent reduction in heat exchange efficiency due to the backflow of the conditioned air in the plurality of ducts  20 . 
     Alternatively, the air treatment system  1  includes each air deflector  74  of each blower unit  70  attached to each duct  20 , and the air deflector motor  75  for driving each air deflector  74 . The main controller  40  controls to adjust the opening degrees of the plurality of air deflectors  74  to prevent backflow, in the plurality of ducts  20 , of the conditioned air flowing from the heat exchanger unit  10  toward the plurality of openings  71 . As a result, it is possible to easily prevent reduction in heat exchange efficiency due to the backflow of the conditioned air in the plurality of ducts  20 . 
     (9-14) 
     The air treatment system  1  of the first embodiment includes a plurality of fan motors  38  configured to change the amount of air supplied by each of the plurality of fan units  30 . The air treatment system  1  controls the backflow of the conditioned air in each duct  20  by adjusting the rotation speed of each fan motor  38 , which makes it easy to prevent reduction in heat exchange efficiency due to the backflow of the conditioned air in each duct  20 . 
     (10) Modification to the Second Embodiment 
     (10-1) Modification 2A 
     In the second embodiment, the description is given of the case where the fan motor  38  functions as an actuator for changing the amount of air supplied. However, the actuator for changing the amount of air supplied in the second embodiment is not limited to the fan motor  38 . For example, the plurality of actuators may be the driving motor of the damper shown in  FIG. 5 . The fan motor  38  of the fan  32  shown in  FIG. 5  may be a motor of a type capable of changing the rotation speed similar to that of the second embodiment, or may be a motor of a type incapable of changing the rotation speed. In a case where the fan motor  38  is the motor of a type incapable of changing the rotation speed, the amount of air supplied (air flow volume) from the fan unit  30  to the blower unit  70  is changed only by the damper, for example. On the other hand, in a case where the fan motor  38  is the motor of a type capable of changing the rotation speed, the amount of air supplied (air flow volume) from the fan unit  30  to the blower unit  70  is changed not only with change in the opening degree of the damper but with change in the rotation speed of the fan motor  38 . In such a case, the fan controller  34  may be so configured to control both the driving motor and the fan motor  38  as the actuators. 
     In a case where the fan motor  38  is the motor of a type incapable of changing the rotation speed and the amount of air (air flow volume) supplied from the fan unit  30  to the blower unit  70  is changed only by the damper, a damper controller is provided instead of the fan controller  34 . The main controller  40  sends the calculated amount of air supplied to the plurality of damper controllers as the target air supply amount. The main controller  40  sends, for example, the target air supply amount of the fan units  30   a  to  30   d  to the damper controllers attached to the fan units  30   a  to  30   d . The target air supply amount of the fan units  30   a  to  30   d  is a command concerning the amount of air supplied by the fan unit  30 . In other words, the main controller  40  sends a plurality of commands to the plurality of damper controllers for controlling the fan units  30   a  to  30   d . The damper controllers of the fan units  30   a  to  30   d  control the opening degrees of the dampers to bring the amount of air supplied closer to the target air supply amount. 
     More specifically, for example, the damper controller of each of the fan units  30   a  to  30   d  compares volume of air (amount of air supplied) passing through the fan unit  30   a  detected by the differential pressure sensor  121  of each of the fan units  30   a  to  30   d  with the target air flow volume (target air supply amount). In a case where the volume of the air passing through the fan units  30   a  to  30   d  is smaller than the target air flow volume, the damper controller of each of the fan units  30   a  to  30   d  increases the opening degree of the damper with the driving motor and increases the air flow volume (amount of air supplied) of the fan units  30   a  to  30   d  to bring the air flow volume closer to the target air flow volume. Conversely, in a case where the volume of the air passing through the fan units  30   a  to  30   d  is greater than the target air flow volume, the opening degrees of the dampers are reduced by the driving motors and reduce the air flow volume (amount of air supplied) of the fan units  30   a  to  30   d  to bring the air flow volume closer to the target air flow volume. 
     For example, the plurality of actuators may be the air deflector motor  75 . The fan motor  38  of the fan  32  may be a motor of a type capable of changing the rotation speed similar to that of the second embodiment, or may be a motor of a type incapable of changing the rotation speed. In a case where the fan motor  38  is the motor of a type incapable of changing the rotation speed, the amount of air supplied (air flow volume) from the fan unit  30  to the blower unit  70  is changed by both or any one of the damper and the air deflector  74 , for example. On the other hand, in a case where the fan motor  38  is the motor of a type capable of changing the rotation speed, the amount of air supplied (air flow volume) from the fan unit  30  and the blower unit  70  to the air conditioned space TS is changed not only with change in the opening degree of both or any one of the damper and the air deflector  74  but with change in the rotation speed of the fan motor  38 . 
     In a case where the fan motor  38  is the motor of a type incapable of changing the rotation speed and the amount of air (air flow volume) supplied from the fan unit  30  to the blower unit  70  is changed only by the air deflector  74 , an air deflector controller is provided instead of the fan controller  34 . The main controller  40  sends the calculated amount of air supplied to the plurality of air deflector controllers as the target air supply amount. The main controller  40  sends, for example, the target air supply amount of the fan units  30   a  to  30   d  to the air deflector controllers attached to the fan units  30   a  to  30   d . The target air supply amount of the fan units  30   a  to  30   d  is a command concerning the amount of air supplied by the fan units  30   a  to  30   d . In other words, the main controller  40  sends a plurality of commands to the plurality of air deflector controllers for controlling the fan units  30   a  to  30   d . The air deflector controllers of the fan units  30   a  to  30   d  control the opening degrees of the air deflectors  74  to bring the amount of air supplied closer to the target air supply amount. 
     More specifically, for example, the air deflector controller of each of the fan units  30   a  to  30   d  compares volume of air (amount of air supplied) passing through the fan unit  30   a  detected by the differential pressure sensor  121  of each of the fan units  30   a  to  30   d  with the target air flow volume (target air supply amount). In a case where the volume of the air passing through the fan units  30   a  to  30   d  is smaller than the target air flow volume, the air deflector controller of each of the fan units  30   a  to  30   d  increases the opening degree of the air deflector  74  with the air deflector motor  75  and increases the air flow volume (amount of air supplied) of the fan units  30   a  to  30   d  to bring the air flow volume closer to the target air flow volume. Conversely, in a case where the volume of the air passing through the fan units  30   a  to  30   d  is greater than the target air flow volume, the opening degree of the air deflector  74  are reduced by the air deflector motors  75  and reduces the air flow volume (amount of air supplied) of the fan units  30   a  to  30   d  to bring the air flow volume closer to the target air flow volume. 
     (11) Additional Description of the Modifications and the Second Embodiment 
     (11-1) 
     The air treatment system  1  of the second embodiment has characteristic similar to those of the first embodiment described above in (9-1). 
     (11-2) 
     The controller  400  of the second embodiment controls a plurality of actuators in accordance with a plurality of commands concerning the amount of air supplied by the plurality of fan units  30   a  to  30   d . The actuator of the second embodiment is at least one of the fan motor  38 , the driving motor, and the air deflector motor  75 . Such control enables the air treatment system  1  to adjust the volume of air passing through the use side heat exchanger  11  for efficient heat exchange in the use side heat exchanger  11 , leading to the reduction in energy consumption of the air treatment system  1 . In the second embodiment, at least one of the plurality of fan controllers  34 , the plurality of damper controllers, and the plurality of air deflector controllers of the controller  400  controls the plurality of actuators. 
     (11-3) 
     The controller  400  of the air treatment system  1  of the second embodiment includes the main controller  40  for sending a plurality of commands and at least one sub-controller for receiving the plurality of commands from the main controller  40 . Examples of the sub controller of the second embodiment include the fan controller  34 , the damper controller, and the air deflector controller. At least one sub-controller controls the plurality of actuators on the basis of the plurality of commands. For example, in a case where the plurality of actuators is only the plurality of fan motors  38 , the fan controllers  34  and the fan motors  38  may be provided in a one-to-one correspondence. Alternatively, the plurality of fan motors  38  may be provided so as to correspond to one fan controller  34 . In such an air treatment system  1 , since the main controller  40  controls the plurality of actuators through at least one sub controller, the control by the main controller  40  is simplified to facilitate the duct design and the layout change in the system. 
     (11-4) 
     In the air treatment system  1  of the second embodiment, each of the plurality of fan units  30   a  to  30   d  includes the differential pressure sensor  121  or a wind speed sensor that is an air flow volume detection unit for detecting volume of air passing through the unit. Each of the plurality of sub-controllers controls the rotation speed of the fan motors  38   a  to  33   d  in a manner to bring the air flow volume detected by the air flow volume detection unit closer to the amount of air supplied instructed by the controller  400 . This allows the controller  400  to reliably control the amount of air supplied by the fan units  30   a  to  30   d.    
     (11-5) 
     In the air treatment system  1  of the second embodiment, the controller  400  calculates the amount of air supplied by each of the fan units  30   a  to  30   d  on the basis of the temperature difference between the indoor air temperature to be adjusted by each of the plurality of fan units  30   a  to  30   d  and the set temperature and air flow temperature, and determines a plurality of commands on the basis of the calculated amount of air supplied. This allows the air treatment system  1  to easily control the temperature of the air conditioned space TS by changing the amount of air supplied. 
     (12) Modification to the Third Embodiment 
     (12-1) Modification 3A 
     In the third embodiment, the description is given of the case where the main controller  40  determines the output of the blower  29  in such a manner that, among the plurality of fans  32 , the rotation speed of a fan with the highest fan efficiency is the maximum. 
     However, another configuration is possible in which the main controller  40  determines the output of the blower  29  in such a manner that, among the plurality of fans  32 , the rotation speed of a fan with the lowest fan efficiency is the minimum. In such a case, for each of the fan units  30  other than the fan unit  30  with the lowest fan efficiency, the corresponding fan controller  34  adjusts the rotation speed of the fan  32 . The rotation speed of the plurality of fans  32  is adjusted independently of one another. 
     Further, in a case where the main controller  40  reduces the target air flow volume, the main controller  40  may be configured to determine the output of the blower  29  so that the treatment static pressure of the fan with the highest fan efficiency among the plurality of fans  32  is constant. With such a configuration, the fan unit  30  having a constant treatment static pressure among the fan units  30  can keep the rotation speed of the fan  32  higher in efficiency than the others, so that the entire efficiency of the air treatment system  1  can be kept high. As described above, in the case of using the configuration in which the treatment static pressure is kept constant, for example, each fan unit  30  is configured to include a differential pressure sensor  43  (see  FIG. 15 ) for detecting the treatment static pressure of the fan  32 . Alternatively, the controller  400  is so configured as to calculate the treatment static pressure on the basis of the detection result of the air flow volume detection unit  33  and the rotation speed of the fan  32 . The controller  400  determines the output of the blower  29  on the basis of the detected value of the differential pressure sensor  43  of the fan unit  30  with the highest fan efficiency. In such a case, for each of the fan units  30  other than the fan unit  30  with the treatment static pressure kept at constant, the corresponding fan controller  34  adjusts the rotation speed of the fan  32 . The rotation speed of the plurality of fans  32  is adjusted independently of one another. 
     Further, in a case where the main controller  40  increases the target air flow volume, the main controller  40  may be configured to determine the output of the blower  29  so that the treatment static pressure of the fan with the lowest fan efficiency among the plurality of fans  32  is constant. With such a configuration, the fan unit  30  having a constant treatment static pressure among the fan units  30  can keep the rotation speed of the fan  32  lower in efficiency than the others, so that the entire efficiency of the air treatment system  1  can be kept high. As described above, in the case of using the configuration in which the treatment static pressure is kept constant, for example, each fan unit  30  is configured to include a differential pressure sensor  43  (see  FIG. 15 ) for detecting the treatment static pressure of the fan  32 . Alternatively, the controller  400  is so configured as to calculate the treatment static pressure on the basis of the detection result of the air flow volume detection unit  33  and the rotation speed of the fan  32 . The controller  400  determines the output of the blower  29  on the basis of the detected value of the differential pressure sensor  43  of the fan unit  30  with the lowest fan efficiency. In such a case, for each of the fan units  30  other than the fan unit  30  with the treatment static pressure kept at constant, the corresponding fan controller  34  adjusts the rotation speed of the fan  32 . The rotation speed of the plurality of fans  32  is adjusted independently of one another. 
     (12-2) Modification 3B 
     In the third embodiment, the description is given of the case where the remote sensor  170  includes a temperature sensor, however, the remote sensor  170  may have, for example, a function of at least one of a temperature sensor, a CO 2  concentration sensor, and a humidity sensor. With this configuration, each of the plurality of fan controllers  34  receives at least one detected value of the temperature, the CO 2  concentration, and the humidity of the air conditioned space TS from the remote sensor  170  connected to the fan controllers  34 . Each fan controller  34  holds data on a set value of a detection target of the remote sensor  170 . Each fan controller  34  sends a set value of at least one of the temperature, the CO 2  concentration, and the humidity to the main controller  40 . The main controller  40  determines a target air flow volume of each fan unit  30  according to the value detected by the corresponding remote sensor  170  on the basis of the set value. The main controller  40  sends a value of the target air flow volume to each fan controller  34 . 
     (12-3) Modification 3C 
     In the third embodiment, the description is given of the case where the heat exchanger unit  10  includes the use side heat exchanger  11 . However, another configuration is possible in which the heat exchanger unit  10  does not have the use side heat exchanger  11 . The air treatment system  1  may be configured as, for example, a system to ventilate the air conditioned space TS when the CO 2  concentration in the air conditioned space TS is high. 
     (12-4) Modification 3D 
     The controller  400  is implemented by a computer. The controller  400  includes control computing devices  40   a  and  34   a  and storage devices  40   b  and  34   b . The control computing devices  40   a  and  34   a  each may be a processor such as a CPU or a GPU. The control computing devices  40   a  and  34   a  read out a program stored in the storage devices  40   b  and  34   b  and perform predetermined image processing and computing processing in accordance with the program. Further, the control computing devices  40   a  and  34   a  can write an computing result to the storage devices  40   b  and  34   b  and read out information stored in the storage devices  40   b  and  34   b  in accordance with the program.  FIGS. 7 and 17  are diagrams showing various functional blocks controlled by the control computing devices  40   a  and  34   a  of the air treatment system of  FIGS. 6 and 16 . The storage devices  40   b  and  34   b  can be used as databases. 
     (12-5) Modification 3E 
     As shown in  FIGS. 16 and 17 , an outside air introduction unit  150  may be attached to the heat exchanger unit  10 . The outside air introduction unit  150  includes an outside air fan  151  and an outside air flow volume sensor  152 . The outside air introduction unit  150  takes in outside air OA from the outside of the air conditioned space TS with the outside air fan  151  and sends air to the heat exchanger unit  10 . The outside air flow volume sensor  152  detects amount of air blowing of the outside air OA sent to the heat exchanger unit  10 . The outside air flow volume sensor  152  sends a value of the detected amount of air blowing of the outside air OA to the main controller  40 . A configuration is possible in which, in the case where the outside air introduction unit  150  sends the outside air OA to the heat exchanger unit  10 , the main controller  40  performs correction according to the air flow volume of the outside air OA with respect to the control over the output of the blower  29 . The outside air flow volume sensor  152  may be, for example, an air flow volume sensor, a wind speed sensor, or a differential pressure sensor. 
     (13) Additional Description of the Modification and the Third Embodiment 
     (13-1) 
     In the air treatment system  1  of the third embodiment, the controller  400  controls the output of the blower  29  to an appropriate value in accordance with the total of supply air volume to be supplied to the air conditioned space TS. The total of supply air volume is an example of the amount of air supplied by the plurality of fans  32 . Such control of the controller  400  enables the air treatment system  1  to reduce the energy consumption of the entire system. 
     (13-2) 
     In the air treatment system  1  of the third embodiment, the heat exchanger unit  10  can exchange heat with the heating medium in the use side heat exchanger  11  and send conditioned air to the plurality of fan units  30 . The plurality of fan units  30  can use the conditioned air to perform air conditioning in the air conditioned space TS. 
     (13-3) 
     The controller  400  of the air treatment system  1  determines the air flow volume of the air supplied by the plurality of fan units  30  according to at least one of the temperature, the humidity, and the CO 2  concentration of the air conditioned space TS to control the air flow volume of each of the plurality of fan units  30 . In such an air treatment system  1 , the controller  400  can control the air flow volume of each of the plurality of fan units  30  to keep at least one of the temperature, the humidity, and the CO 2  concentration of the air conditioned space TS to an appropriate range. 
     (13-4) 
     The air treatment system  1  may be so configured that, when changing the operating state of at least one fan  32  among the plurality of fans  32  or the air flow volume of at least one fan  32  among the plurality of fans  32 , the controller  400  gives priority to increasing the output of a fan with high fan efficiency or reducing the output of a fan with low fan efficiency among the blower  29  and the plurality of fans  32 . In the air treatment system  1  configured as described above, the controller  400  controls the output of the fan with high fan efficiency to be preferentially increased or the output of the fan with low fan efficiency to be decreased, leading to the reduction in energy consumption of the air treatment system  1 . 
     (13-5) 
     The air treatment system  1  can be so configured that the controller  400  determines the output of the blower  29  so that the treatment static pressure of the fan  32  with the highest fan efficiency among the plurality of fans  32  becomes constant or the rotation speed of the fan  32  with the highest fan efficiency among the plurality of fans  32  becomes maximum, so that the output of the fan  32  with low fan efficiency can be reduced preferentially. In such a configuration, as a result of the preferentially reducing the output of the fan  32  with low fan efficiency, the energy consumption can be reduced as compared with the case of reducing the output of the fan  32  with higher fan efficiency. 
     (13-6) 
     The air treatment system  1  can be so configured that the controller  400  determines the output of the blower  29  so that the treatment static pressure of the fan  32  with the lowest fan efficiency among the plurality of fans  32  becomes constant or the rotation speed of the fan  32  with the lowest fan efficiency among the plurality of fans  32  becomes minimum, so that the output of the fan  32  with high fan efficiency can be increased preferentially. In such a configuration, as a result of the preferentially increasing the output of the fan  32  with high fan efficiency, the energy consumption can be reduced as compared with the case of increasing the output of the fan  32  with lower fan efficiency. 
     (13-7) 
     In the air treatment system  1 , the controller  400  increases the output of the blower  29  if the air flow volume of the fan with the maximum fan efficiency among the plurality of fans  32  does not reach the target air flow volume. In the air treatment system  1  configured as described above, the controller  400  can increase the output of the blower  29  and perform control so that the air flow volume of the fan with the maximum fan efficiency among the plurality of fans  32  reaches the target air flow volume. 
     The embodiment of the present disclosure has been described above. Various modifications to modes and details should be available without departing from the object and the scope of the present disclosure recited in the claims. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1 : Air treatment system 
               10 : Heat exchanger unit (example of air treatment unit) 
               30 : Fan unit 
               31 : Unit casing 
               32 : Fan 
               33 : Air flow volume detection unit 
               34 : Fan controller (example of control unit) 
               39 : Fan casing 
               60 : Remote controller 
               300 : Fan unit system 
           
         
       
    
     CITATIONS LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP 2001-304614 A