Patent Description:
Conventional air conditioning systems configured to condition air in a building include an air conditioning system described in <CIT> or the like, which is configured to supply, with use of ducts, a plurality of places in a building with conditioned air obtained by heat exchange in a utilization heat exchanger.

<CIT> refers to a low temperature air conditioning system which provides primary air through smaller than normal ductwork and at a lower than normal temperature at peak load conditions. The primary air is mixed in branch ducts with return air taken from the conditioned space. Low pressure fans pull the return air into mixing boxes equipped with dampers which maintain the downstream temperature in the branch ducts at a normal supply air temperature. Variable air volume terminal units discharge the air into the conditioned space. The document <CIT> discloses a control of an indoor unit side fan based on the external static pressure.

<CIT>, however, does not describe relation between consideration of heat source operation in the air conditioning system and heat exchange in the utilization heat exchanger. The heat source operation may stop or be in trouble due to airflow volume through the utilization heat exchanger.

Such an air conditioning system configured to supply a plurality of places in a building with conditioned air with use of ducts has a task of inhibiting malfunction of the air conditioning system due to airflow volume through a utilization heat exchanger.

An air conditioning system according to the present disclosure is defined in independent claim <NUM>.

An air conditioning system according to a first aspect includes a heat exchanger unit having a utilization heat exchanger, and is configured to generate conditioned air through heat exchange in the utilization heat exchanger and supply an air conditioning target space with the conditioned air through a plurality of distribution flow paths communicating with the heat exchanger unit. The distribution flow paths each include a duct connected to the heat exchanger unit and provided for distribution of the conditioned air, and a fan unit provided correspondingly to the duct and configured to supply the air conditioning target space with the conditioned air from the heat exchanger unit through the duct, as well as an actuator configured to individually change supply air volume of the conditioned air supplied to the air conditioning target space. The air conditioning system includes a main controller configured to control the actuators such that airflow volume through the utilization heat exchanger satisfies a predetermined condition. At least either the ducts or the fan units each include an airflow volume sensing unit. The main controller is configured to total airflow volume through the distribution flow paths detected by the airflow volume sensing units and control the actuators such that a total satisfies the predetermined condition. The actuators are fan motors of the fan units. The main controller controls numbers of revolutions of the fan motors in accordance with values of the airflow volume sensing units.

In the air conditioning system according to the first aspect, the main controller controls the actuators such that the airflow volume through the utilization heat exchanger satisfies the predetermined condition. This configuration inhibits malfunction of the air conditioning system by means of the airflow volume through the utilization heat exchanger.

In the air conditioning system according to the first aspect, the main controller can accurately obtain the airflow volume through the utilization heat exchanger and can accurately inhibit heat source malfunction.

In the air conditioning system according to the first aspect, the numbers of revolutions of the plurality of fan motors are controlled in accordance with the values of the airflow volume sensing units, and the main controller can thus easily control such that the airflow volume through the utilization heat exchanger satisfies the predetermined condition.

An air conditioning system according to a second aspect is the system according to the first aspect, in which each of the actuators is an opening-closing device configured to adjust an opening degree of a damper included in each of the fan units, and the main controller controls the opening degree of the damper by means of the opening-closing device in accordance with the value of the airflow volume sensing unit.

In the air conditioning system according to the second aspect, the main controller controls the opening degrees of the dampers by means of the opening-closing devices in accordance with values of the airflow volume sensing units. This configuration facilitates control such that the airflow volume through the utilization heat exchanger satisfies the predetermined condition.

An air conditioning system according to a third aspect is the system according to the first or second aspect, in which the predetermined condition is to cause the airflow volume through the utilization heat exchanger to be a predetermined value or more.

In the air conditioning system according to the third aspect, the actuators are controlled such that the airflow volume through the utilization heat exchanger is the predetermined value or more. This configuration inhibits malfunction of the air conditioning system, which is caused by insufficient heat exchange in the utilization heat exchanger due to the airflow volume through the utilization heat exchanger being less than the predetermined value.

An air conditioning system according to a fourth aspect is the system according to the third aspect, and the air conditioning system further includes a heat source device connected to the utilization heat exchanger, including a compressor, and constituting a refrigerant circuit configured to achieve a vapor compression refrigeration cycle along with the utilization heat exchanger. The main controller links control of the actuators with control of the refrigerant circuit.

The air conditioning system according to the fourth aspect links control of the actuators with control of the refrigerant circuit, and can thus appropriately control the airflow volume through the utilization heat exchanger by means of the actuators in accordance with a state of the refrigerant circuit, to achieve efficient operation.

An air conditioning system according to a fifth aspect is the system according to the fourth aspect, in which the predetermined value is set to vary in accordance with a parameter of the heat source device influencing a state or circulation volume of a refrigerant circulating in the refrigerant circuit.

The air conditioning system according to the fifth aspect causes the utilization heat exchanger to exchange heat suitably for the state or the circulation volume of the refrigerant circulating in the refrigerant circuit, to achieve an appropriate state of the refrigerant passing the utilization heat exchanger and inhibit malfunction of the heat source device.

An air conditioning system according to a sixth aspect is the air conditioning system according to the fifth aspect, in which the parameter has a value relevant to the circulation volume.

The air conditioning system according to the sixth aspect causes the utilization heat exchanger to exchange heat at the predetermined value of the appropriate airflow volume suitable for the circulation volume of the refrigerant circulating in the refrigerant circuit, to inhibit malfunction of the heat source device.

An air conditioning system according to a seventh aspect is the system according to the fifth aspect, in which the parameter includes at least one of condensation temperature of the refrigerant circuit, evaporation temperature of the refrigerant circuit, heat exchanger temperature of the utilization heat exchanger, an operating frequency of the compressor, combination of inlet temperature and outlet temperature of the utilization heat exchanger, and combination of inlet pressure and the outlet temperature of the utilization heat exchanger.

The air conditioning system according to the seventh aspect causes the utilization heat exchanger to exchange heat suitably for the state or the circulation volume of the refrigerant circulating in the refrigerant circuit to suppress energy consumption of the air conditioning system.

An air conditioning system according to an eighth aspect is the system according to any one of the third to seventh aspects, in which the main controller activates the fan unit being stopped when the airflow volume through the utilization heat exchanger is less than the predetermined value in accordance with a command to reduce airflow volume of the fan unit.

The air conditioning system according to the eighth aspect can suppress increase in airflow volume per fan unit, and can avoid a partial temperature gap from desired temperature in the air conditioning target space.

An air conditioning system according to a ninth aspect is the system according to any one of the third to eighth aspects, in which the main controller increases airflow volume of the fan unit when the airflow volume through the utilization heat exchanger is less than the predetermined value in accordance with a command to reduce the airflow volume of the fan unit.

The air conditioning system according to the ninth aspect allocates the airflow volume to each operating one of the fan units, with no need to operate the fan unit commanded to stop. This configuration reliably stops the fan unit for a place desired to stop air conditioning, and inhibits the air conditioning system from operating not in accordance with a user request.

<FIG> depicts an air conditioning system <NUM> configured to supply an air conditioning target space SA with conditioned air. Examples of the air conditioning target space SA include rooms RA1 and RA2 in a building BL. Description is made to the case where the air conditioning target space SA includes the two rooms RA1 and RA2. The air conditioning system <NUM> is adapted for rooms having various sizes and various shapes, as well as for any number of rooms. The air conditioning target space SA to be supplied with conditioned air from the air conditioning system <NUM> has a circumference (front, rear, upper, lower, right, and left ends) preferably surrounded with wall surfaces like the rooms RA1 and RA2. The air conditioning target space SA is not limited to the rooms RA1 and RA2, but may alternatively include a passage, stairs, an entrance, or the like.

As depicted in <FIG>, the air conditioning system <NUM> includes a heat exchanger unit <NUM> having a utilization heat exchanger <NUM>, and a main controller <NUM>. The air conditioning system <NUM> generates conditioned air through heat exchange in the utilization heat exchanger <NUM>, and supplies the air conditioning target space SA with the conditioned air through a plurality of distribution flow paths communicating with the heat exchanger unit <NUM>. The distribution flow paths each include a duct <NUM> connected to the heat exchanger unit <NUM> and provided for distribution of conditioned air, and a fan unit <NUM> provided correspondingly to the duct <NUM> and configured to supply the air conditioning target space SA with conditioned air from the heat exchanger unit <NUM> through the duct <NUM>. Each of the distribution flow paths further includes an actuator configured to individually change supply air volume of conditioned air supplied to the air conditioning target space SA.

For distinction between the plurality of ducts <NUM>, the reference sign additionally includes an alphabet subscript such as 20a. In this case, the ducts <NUM> include four ducts 20a to 20d. Similarly, the fan units <NUM> include four fan units 30a to 30d. Furthermore, there are provided blow-out port units <NUM> and remote controllers <NUM> including four blow-out port units 70a to 70d and four remote controllers 60a to 60d, respectively.

The heat exchanger unit <NUM> has a function of generating conditioned air through heat exchange in the utilization heat exchanger <NUM>. Each of the ducts <NUM> has a first end <NUM> connected to the heat exchanger unit <NUM>. The plurality of ducts <NUM> is a plurality of pipes provided to send conditioned air generated by the heat exchanger unit <NUM>, and has a function of distributing conditioned air.

The plurality of fan units <NUM> is connected to second ends <NUM> of the plurality of ducts <NUM>. In this case, one of the ducts 20a connected to the heat exchanger unit <NUM> is connected with the corresponding single fan unit 30a. Similarly, the fan units 30b to 30d are connected to the corresponding ducts 20b to 20d, respectively. Description is made to the case where the ducts <NUM> each have the single first end <NUM> and the single second end <NUM>. The single duct <NUM> may alternatively be branched to have a single first end <NUM> and a plurality of second ends <NUM>. In this case, the fan units <NUM> may be respectively connected to the plurality of second ends <NUM> thus branched. The fan units 30a to 30d are connected to the blow-out port units 70a to 70d and the remote controllers 60a to 60d.

The air conditioning system <NUM> includes a plurality of air outlet <NUM> disposed in the air conditioning target space SA. Each of the fan units <NUM> supplies a corresponding one of the air outlet <NUM> with conditioned air. In order to supply the air outlet <NUM> with conditioned air, the fan units <NUM> suck conditioned air from the heat exchanger unit <NUM> through the ducts <NUM>. Each of the fan units <NUM> includes a fan <NUM> accommodated in a casing <NUM> of the fan unit <NUM> in order to suck conditioned air. Each of the fans <NUM> sends air from the second end <NUM> of the corresponding duct <NUM> toward the corresponding blow-out port <NUM>. Each of the fan units <NUM> may include a single or a plurality of fans <NUM>. In this case, the casings <NUM> of the fan units 30a to 30d accommodate fans 32a to 32d one by one.

The air conditioning system <NUM> is configured to individually change, by means of the actuators, the supply air volume of conditioned air supplied to the air outlet <NUM>. In this case, each of the actuators is a fan motor <NUM> having a variable rotation speed. There are provided four fan motors 33a to 33d having individually variable numbers of revolutions in this case. The fan motors 33a to 33d are individually varied in the numbers of revolutions to achieve individual change in supply air volume of the fan units 30a to 30d.

The main controller <NUM> in the air conditioning system <NUM> transmits commands on increase or decrease in supply air volume to the plurality of actuators. The air conditioning system <NUM> including the main controller <NUM> will be described later in terms of its control system.

The air conditioning system <NUM> further includes, in addition to the configurations described above, a heat source unit <NUM>, the remote controllers <NUM>, the blow-out port units <NUM>, a blow-in port unit <NUM>, and various sensors. The sensors included in the air conditioning system <NUM> will be described later.

The heat exchanger unit <NUM> includes the utilization heat exchanger <NUM>, a hollow housing <NUM> accommodating the utilization heat exchanger <NUM>, and the main controller <NUM>. The housing <NUM> has a single air inlet port 12a connected to a blow-in port <NUM>, and a plurality of air outlet ports 12b connected to the plurality of ducts <NUM>. Exemplified below is the case where there is provided the single air inlet port 12a. There may alternatively be provided a plurality of air inlet ports 12a. The utilization heat exchanger <NUM> is exemplarily of a fin and tube type, and causes heat exchange between air passing between heat transfer fins and a refrigerant flowing in a heat transfer tube. When air sucked through the air inlet port 12a passes the utilization heat exchanger <NUM>, heat is exchanged between the air and the refrigerant passing the utilization heat exchanger <NUM> to generate conditioned air. The conditioned air generated by the utilization heat exchanger <NUM> is sucked into the ducts 20a to 20d through the air outlet ports 12b.

The heat exchanger unit <NUM> does not include any fan. The heat exchanger unit <NUM> can suck air through the air inlet port 12a because the heat exchanger unit <NUM> has internal negative pressure when all the ducts <NUM> suck air through the plurality of air outlet ports 12b.

The plurality of ducts <NUM> having the function of distributing conditioned air connects the plurality of air outlet ports 12b of the heat exchanger unit <NUM> and the plurality of fan units <NUM>. Description is made to the case where the fan units <NUM> and the blow-out port units <NUM> are connected directly. Each of the fan units <NUM> and the corresponding blow-out port unit <NUM> may alternatively interpose the duct <NUM> to connect the fan unit <NUM> and the blow-out port unit <NUM>.

Examples of the duct <NUM> may include a metal pipe having a fixed shape, and a pipe made of a freely bent material. The ducts <NUM> thus configured are connected to enable various dispositions of the heat exchanger unit <NUM>, the plurality of fan units <NUM>, and the plurality of blow-out port units <NUM>.

<FIG> conceptually depicts the heat exchanger unit <NUM>, the four fan units <NUM>, and the four blow-out port units <NUM> connected in a ceiling space chamber AT. The heat exchanger unit <NUM>, the fan units <NUM>, and the blow-out port units <NUM> thus configured are easily formed to be thin and may accordingly be disposed in a space below a floor of a room RA1 or RA2.

Examples of the fan <NUM> included in each of the fan units <NUM> can include a centrifugal fan. Examples of the centrifugal fan adopted as the fan <NUM> include a sirocco fan. The casing <NUM> included in each of the fan units <NUM> has an intake port <NUM> and an exhaust port <NUM>. The intake port <NUM> of each of the casings <NUM> is connected with the second end <NUM> of a corresponding one of the ducts <NUM>. The exhaust port <NUM> of each of the casings <NUM> is connected with a blow-out port of a corresponding one of the fans <NUM> and is also connected with a corresponding one of the blow-out port units <NUM>. Conditioned air blown out of the fan <NUM> passes the blow-out port unit <NUM> and is blown out of the blow-out port <NUM>.

The unit casing <NUM> is provided with a fan controller <NUM>. All the fan controllers <NUM> are connected to the main controller <NUM> in this case.

<FIG> depicts the sirocco fan exemplifying the fan <NUM>. The fan motor <NUM> configured to rotate a fan rotor <NUM> of the fan <NUM> has a variable rotation speed. The fan <NUM> can thus be changed in supply air volume by change in the rotation speed of the fan motor <NUM>. The fan controllers <NUM> are each connected to the corresponding fan motor <NUM> and is configured to control the rotation speed of the fan motor <NUM>.

The fan units <NUM> each include a differential pressure sensor <NUM> functioning as an airflow volume sensing unit to be described later, and each of the fan controllers <NUM> is configured to automatically correct the rotation speed of the fan motor <NUM> needed to generate necessary supply air volume even if the ducts <NUM> extending to the fan units <NUM> generate air resistance varied due to duct lengths. The fan units <NUM> do not need to have such a correcting function in some cases.

The heat source unit <NUM> supplies heat energy necessary for heat exchange in the utilization heat exchanger <NUM> in the heat exchanger unit <NUM>. In the air conditioning system <NUM> depicted in <FIG>, a refrigerant circulates between the heat source unit <NUM> and the heat exchanger unit <NUM> to achieve a vapor compression refrigeration cycle. The heat source unit <NUM> and the heat exchanger unit <NUM> constitute a refrigeration cycle apparatus configured to achieve the vapor compression refrigeration cycle. <FIG> exemplifies the heat source unit <NUM> that is disposed outside the building BL and utilizes outdoor air as a heat source. However, the heat source unit <NUM> can be disposed at a place not limited to the outside of the building BL.

The heat source unit <NUM> includes a compressor <NUM>, a heat source heat exchanger <NUM>, an expansion valve <NUM>, a four-way valve <NUM>, a heat source fan <NUM>, a heat source controller <NUM>, and in-unit refrigerant pipes <NUM> and <NUM>. The compressor <NUM> has a discharge port connected to a first port of the four-way valve <NUM>, and a suction port connected to a third port of the four-way valve <NUM>. The compressor <NUM> compresses a gaseous refrigerant (hereinafter, also referred to as a gas refrigerant) or a refrigerant in a gas-liquid two-phase state sucked through the suction port, and discharges the compressed refrigerant from the discharge port. The compressor <NUM> incorporates a compressor motor configured to change a rotation speed (or an operating frequency) through inverter control or the like. The compressor <NUM> is configured to change the operating frequency so as to change discharge volume per unit time of a discharged refrigerant.

The four-way valve <NUM> has a second port connected with a first inlet-outlet port of the heat source heat exchanger <NUM>, and a fourth port connected with the in-unit refrigerant pipe <NUM>. During cooling operation, the four-way valve <NUM> causes the refrigerant to flow, as indicated by a solid line, from the first port to the second port, be discharged from the compressor <NUM>, be sent to the heat source heat exchanger <NUM>, flow from the utilization heat exchanger <NUM> through an in-unit refrigerant pipe <NUM>, a connection pipe <NUM>, and the in-unit refrigerant pipe <NUM>, flow from the fourth port to the third port, and then be sent to the suction port of the compressor <NUM>. During heating operation, the four-way valve <NUM> causes the refrigerant to flow, as indicated by a broken line, from the first port to the fourth port, be discharged from the compressor <NUM>, be sent to the utilization heat exchanger <NUM> through the in-unit refrigerant pipe <NUM>, the connection pipe <NUM>, and the in-unit refrigerant pipe <NUM>, flow from the second port to the third port, and be sent from the heat source heat exchanger <NUM> to the suction port of the compressor <NUM>. The heat source heat exchanger <NUM> is exemplarily of a fin and tube type, and causes heat exchange between air passing between heat transfer fins and a refrigerant flowing in a heat transfer tube.

The heat source heat exchanger <NUM> has a second inlet-outlet port connected to a first end of the expansion valve <NUM>, and a second end of the expansion valve <NUM> is connected to a first inlet-outlet port of the utilization heat exchanger <NUM> via the in-unit refrigerant pipe <NUM>, a connection pipe <NUM>, and an in-unit refrigerant pipe <NUM>. The utilization heat exchanger <NUM> has a second inlet-outlet port connected to the in-unit refrigerant pipe <NUM>.

The heat source unit <NUM> and the heat exchanger unit <NUM> thus configured are connected to constitute a refrigerant circuit <NUM>. During cooling operation, the refrigerant flows, in the refrigerant circuit <NUM>, to the compressor <NUM>, the four-way valve <NUM>, the heat source heat exchanger <NUM>, the expansion valve <NUM>, the utilization heat exchanger <NUM>, the four-way valve <NUM>, and the compressor <NUM> in the mentioned order. During heating operation, the refrigerant flows, in the refrigerant circuit <NUM>, to the compressor <NUM>, the four-way valve <NUM>, the utilization heat exchanger <NUM>, the expansion valve <NUM>, the heat source heat exchanger <NUM>, the four-way valve <NUM>, and the compressor <NUM> in the mentioned order.

During cooling operation, a gas refrigerant compressed by the compressor <NUM> is sent to the heat source heat exchanger <NUM> through the four-way valve <NUM>. This refrigerant radiates heat in the heat source heat exchanger <NUM> to air blown by the heat source fan <NUM>, is expanded at the expansion valve <NUM> to be decompressed, flows through the in-unit refrigerant pipe <NUM>, the connection pipe <NUM>, and the in-unit refrigerant pipe <NUM>, and is sent to the utilization heat exchanger <NUM>. The refrigerant sent from the expansion valve <NUM> and having low temperature and low pressure exchanges heat in the utilization heat exchanger <NUM> to absorb heat from air sent from the blow-in port <NUM>. A gas refrigerant or a gas-liquid two-phase refrigerant having exchanged heat in the utilization heat exchanger <NUM> flows through the in-unit refrigerant pipe <NUM>, the connection pipe <NUM>, the in-unit refrigerant pipe <NUM>, and the four-way valve <NUM>, and is sucked to the compressor <NUM>. Conditioned air reduced in heat in the utilization heat exchanger <NUM> is blown out to the rooms RA1 and RA2 through the plurality of ducts <NUM>, the plurality of fan units <NUM>, and the plurality of air outlet <NUM>, so as to cool the rooms RA1 and RA2.

During cooling operation, the expansion valve <NUM> is controlled to be adjusted in opening degree to cause, for example, a degree of superheating of the refrigerant sucked to the suction port of the compressor <NUM> to match a degree of superheating target value, in order to avoid liquid compression at the compressor <NUM>. Furthermore, the operating frequency of the compressor <NUM> is controlled to change so as to achieve cooling load processing while the expansion valve <NUM> is adjusted in opening degree. The degree of superheating is exemplarily calculated by subtracting evaporation temperature of the refrigerant in the utilization heat exchanger <NUM> from temperature of the gas refrigerant sent from the utilization heat exchanger.

During heating operation, the gas refrigerant compressed by the compressor <NUM> flows through the four-way valve <NUM>, the in-unit refrigerant pipe <NUM>, the connection pipe <NUM>, and the in-unit refrigerant pipe <NUM>, and is sent to the utilization heat exchanger <NUM>. This refrigerant exchanges heat in the utilization heat exchanger <NUM> to give heat to air sent from the blow-in port <NUM>. The refrigerant having exchanged heat in the utilization heat exchanger <NUM> flows through the in-unit refrigerant pipe <NUM>, the connection pipe <NUM>, and the in-unit refrigerant pipe <NUM>, and is sent to the expansion valve <NUM>. The refrigerant expanded and decompressed by the expansion valve <NUM> and having low temperature and low pressure is sent to the heat source heat exchanger <NUM>, and exchanges heat in the heat source heat exchanger <NUM> to absorb heat from air blown by the heat source fan <NUM>. A gas refrigerant or a gas-liquid two-phase refrigerant having exchanged heat in the heat source heat exchanger <NUM> flows through the four-way valve <NUM> and is sucked to the compressor <NUM>. Conditioned air obtained heat in the utilization heat exchanger <NUM> is blown out to the rooms RA1 and RA2 through the plurality of ducts <NUM>, the plurality of fan units <NUM>, and the plurality of air outlet <NUM>, so as to heat the rooms RA1 and RA2.

During heating operation, the expansion valve <NUM> is controlled to be adjusted in opening degree to cause, for example, the refrigerant at an outlet port of the utilization heat exchanger <NUM> (the in-unit refrigerant pipe <NUM>) to have a degree of subcooling matching a target value. Furthermore, the operating frequency of the compressor <NUM> is controlled to change so as to achieve heating load processing while the expansion valve <NUM> is adjusted in opening degree. The degree of subcooling of the utilization heat exchanger <NUM> is exemplarily calculated by subtracting temperature of a liquid refrigerant exiting the utilization heat exchanger <NUM> from condensation temperature of the refrigerant in the utilization heat exchanger <NUM>.

Each of the blow-out port units <NUM> is attached to a ceiling CE with the blow-out port <NUM> exemplarily directed downward. The blow-out port unit <NUM> is exemplarily attached to the ceiling CE in this case. The blow-out port unit <NUM> may alternatively be attached to a wall or the like, with no limitation to the ceiling CE in terms of an attachment place of the blow-out port unit <NUM>.

The blow-out port units <NUM> each include a hollow casing <NUM> accommodating an air filter <NUM>. The blow-out port units 70a to 70d are connected to the fan units 30a to 30d, respectively. Conditioned air sent from the fan unit <NUM> passes the air filter <NUM> and is blown out of the blow-out port <NUM>. Description is made to the case where the blow-out port units <NUM> each include the air filter <NUM>. Each of the blow-out port units <NUM> may not alternatively include the air filter <NUM>.

Each of the blow-out port units <NUM> includes a wind direction plate <NUM> accommodated in the hollow casing <NUM>. The blow-out port unit <NUM> includes a wind direction plate motor <NUM> configured to drive the wind direction plate <NUM>. The wind direction plate motor <NUM> configured to drive the wind direction plate <NUM> is an actuator in this case. The wind direction plate <NUM> can be moved by the wind direction plate motor <NUM> to adjust a wind direction. The wind direction plate <NUM> can also be moved to be positioned so as to shut the blow-out port <NUM>. The wind direction plate motor <NUM> is connected to the fan controller <NUM> of the fan unit <NUM> or the like. The fan controller <NUM> can thus control the wind direction as well as can control to open or close the blow-out port <NUM>. Description is made to the case where the blow-out port units <NUM> each include the wind direction plate <NUM> and the wind direction plate motor <NUM>. Each of the blow-out port units <NUM> may not alternatively include the wind direction plate <NUM> or the wind direction plate motor <NUM>.

The blow-in port unit <NUM> is attached to the ceiling CE with the blow-in port <NUM> exemplarily directed toward the air conditioning target space SA. The blow-in port unit <NUM> is exemplarily attached to the ceiling CE in this case. The blow-in port unit <NUM> may alternatively be attached to a wall of the building BL, with no limitation to the ceiling CE in terms of an attachment place of the blow-in port unit <NUM>.

The blow-in port unit <NUM> includes a hollow casing <NUM> accommodating an air filter <NUM>. Air sent to the heat exchanger unit <NUM> passes the air filter <NUM> and is imported through the blow-in port <NUM>. Description is made to the case where the blow-in port unit <NUM> includes the air filter <NUM>. The blow-in port unit <NUM> may not alternatively include the air filter <NUM>.

As depicted in <FIG>, the main controller <NUM> is connected to the plurality of fan controllers <NUM> and the heat source controller <NUM>. The heat source controller <NUM> is exemplarily constituted by various circuits mounted on a printed circuit board connected to various devices included in the heat source unit <NUM>, and controls the various devices in the heat source unit <NUM>, such as the compressor <NUM>, the expansion valve <NUM>, the four-way valve <NUM>, and the heat source fan <NUM>. The main controller <NUM> is connected to the remote controllers <NUM> via the fan controllers <NUM>. The remote controllers 60a to 60d correspond to the blow-out port units 70a to 70d and are connected to the fan units 30a to 30d. Description is made to the case where the remote controllers <NUM> are connected to the main controller <NUM> via the fan controllers <NUM>. The remote controllers <NUM> may alternatively be connected directly to the main controller <NUM>. Exemplified below is the case where the main controller <NUM>, the plurality of fan controllers <NUM>, the heat source controller <NUM>, and the plurality of remote controllers <NUM> are connected wiredly. All or part of the controllers may alternatively be connected by wireless communication.

The main controller <NUM>, the plurality of fan controllers <NUM>, the heat source controller <NUM>, and the plurality of remote controllers <NUM> are each embodied by a computer or the like. The computer constituting each of the main controller <NUM>, the plurality of fan controllers <NUM>, the heat source controller <NUM>, and the plurality of remote controllers <NUM> includes a control computing device and a storage device. Examples of the control computing device can include a processor such as a CPU or a GPU. The control computing device reads a program stored in the storage device and executes predetermined image processing or arithmetic processing in accordance with the program. The control computing device is configured to further write a result of the arithmetic processing to the storage device, and read information stored in the storage device, in accordance with the program. The main controller <NUM>, the plurality of fan controllers <NUM>, the heat source controller <NUM>, and the plurality of remote controllers <NUM> may alternatively be constituted by an integrated circuit (IC) configured to execute control similar to control with use of a CPU and a memory. Examples of the IC mentioned 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 <NUM> is provided with a suction temperature sensor <NUM>, a gas-side temperature sensor <NUM>, a liquid-side temperature sensor <NUM>, and a utilization heat exchanger temperature sensor <NUM>. Examples of these temperature sensors or any temperature sensor to be described later can include a thermistor. There may be optionally provided an air outlet temperature sensor <NUM> configured to detect temperature of air just having passed the utilization heat exchanger <NUM>. The suction temperature sensor <NUM>, the gas-side temperature sensor <NUM>, the liquid-side temperature sensor <NUM>, and the utilization heat exchanger temperature sensor <NUM> are connected to the main controller <NUM> and have detection results transmitted to the main controller <NUM>. The suction temperature sensor <NUM> detects temperature of air sucked through the air inlet port 12a. The gas-side temperature sensor <NUM> detects temperature of a refrigerant at the first inlet-outlet port of the utilization heat exchanger <NUM> connected to the in-unit refrigerant pipe <NUM>. The liquid-side temperature sensor <NUM> detects temperature of a refrigerant at the second inlet-outlet port of the utilization heat exchanger <NUM> connected to the in-unit refrigerant pipe <NUM>. The utilization heat exchanger temperature sensor <NUM> detects heat exchanger temperature with a refrigerant in the gas-liquid two-phase state flowing in the utilization heat exchanger <NUM>.

The heat source unit <NUM> is provided with a heat source air temperature sensor <NUM>, a discharge pipe temperature sensor <NUM>, and a heat source heat exchanger temperature sensor <NUM>. The heat source air temperature sensor <NUM>, the discharge pipe temperature sensor <NUM>, and the heat source heat exchanger temperature sensor <NUM> are connected to the heat source controller <NUM>. The heat source air temperature sensor <NUM>, the discharge pipe temperature sensor <NUM>, and the heat source heat exchanger temperature sensor <NUM> have detection results transmitted to the main controller <NUM> via the heat source controller <NUM>. The heat source air temperature sensor <NUM> detects temperature of an airflow generated by the heat source fan <NUM> and just about to pass the heat source heat exchanger <NUM>. The discharge pipe temperature sensor <NUM> detects temperature of a refrigerant discharged from the compressor <NUM>. The heat source heat exchanger temperature sensor <NUM> is attached adjacent to a halfway portion of a refrigerant flow path in the heat source heat exchanger <NUM>, and detects heat exchanger temperature with a refrigerant in the gas-liquid two-phase state flowing in the heat source heat exchanger <NUM>.

The fan unit <NUM> is provided with the differential pressure sensor <NUM> and a blow-out temperature sensor <NUM>. The differential pressure sensor <NUM> detects differential pressure between airflows upwind and downwind of a place provided with the fan unit <NUM> or the like. The differential pressure sensor <NUM> is connected to the fan controller <NUM>, and transmits, to the fan controller <NUM>, data of the differential pressure thus detected. The differential pressure sensor <NUM> is attached to a place of a flow path exemplarily having a preliminarily determined sectional area, and the fan controller <NUM> is configured to calculate supply air volume from a detection value of the differential pressure sensor <NUM>. The differential pressure sensor <NUM> detects differential pressure to be referred to for detection of a wind direction. The blow-out temperature sensor <NUM> is exemplarily disposed in the casing <NUM> of each of the fan units <NUM>, and detects temperature of conditioned air blown out of the fan unit <NUM>. Description is made to the case where the blow-out temperature sensor <NUM> is disposed in the casing <NUM> of the fan unit <NUM>. The blow-out temperature sensor <NUM> may alternatively be disposed at a different place such as an inside of the blow-out port unit <NUM>.

Each of the remote controllers <NUM> incorporates an indoor temperature sensor <NUM>, and is configured to input a command to turn on or off at least one of the air conditioning system <NUM> and the fan unit <NUM>, switching between cooling operation and heating operation, set temperature, and set airflow volume. For example, the set temperature is provided to enable input by means of a numerical value, and the set airflow volume is provided to enable input through selection among slight airflow volume, small airflow volume, moderate airflow volume, and large airflow volume. A user uses an input button of the remote controller <NUM> to select cooling operation, set <NUM> as set temperature, and select moderate airflow volume as set airflow volume.

The main controller <NUM> calculates, from blow-out temperature detected by each of the blow-out temperature sensors <NUM> and the set temperature, necessary supply air volume to be blown out of the corresponding fan unit <NUM>, controls the rotation speed of the fan motor <NUM>, and controls to approach a detection value of the indoor temperature sensor <NUM> to the set temperature.

Exemplarily assume that three fan units <NUM> are initially connected to the heat exchanger unit <NUM> and one of the air outlet ports 12b is closed in the heat exchanger unit <NUM>. In order to additionally provide another fan unit <NUM> in such a case, the duct <NUM> is connected to the air outlet port 12b having been closed, the additional fan unit <NUM> is connected to the duct <NUM>, and the blow-out port unit <NUM> is connected to the fan unit <NUM> thus added. The fan controller <NUM> of the fan unit <NUM> thus added is connected to the main controller <NUM> to complete a network of the main controller <NUM> and the four fan units <NUM>, through facilitated construction of the network for transmission of commands from the main controller <NUM>.

In the air conditioning system <NUM>, the set airflow volume inputted from the plurality of remote controllers <NUM> corresponds to basic supply air volume for determination of supply air volume of the plurality of fan units <NUM>. However, without change in set airflow volume, cooling operation decreases temperature to be lower than the set temperature and heating operation increases temperature to be higher than the set temperature after the temperature reaches the set temperature. In order to converge indoor air temperature to the set temperature in accordance with a command from the main controller <NUM>, the supply air volume of each of the fan units <NUM> is changed from the set airflow volume. The main controller <NUM> calculates an air conditioning load from a difference between the indoor air temperature and the set temperature, and determines necessary supply air volume from the air conditioning load and blowing air temperature of each of the fan units <NUM>. The air conditioning load is zero in an exemplary case where the indoor air temperature matches the set temperature without any difference therebetween. The main controller <NUM> accordingly causes the fan unit <NUM> having indoor air temperature matching the set temperature to stop blowing air even if the set airflow volume is not zero. Alternatively, in order to prevent an air backflow from the blow-out port <NUM> toward the heat exchanger unit <NUM>, the fan unit <NUM> to be stopped in accordance with the air conditioning load may be controlled not to have no supply air volume for inhibition of the backflow.

The fan controllers <NUM> of the fan units 30a to 30d transmit, to the main controller <NUM>, supply air volume from the fan units 30a to 30d in accordance with the set airflow volume of the four remote controllers <NUM>. When the fan unit <NUM> being stopped is operating to blow air quite slightly in order to prevent an air backflow from the blow-out port <NUM> toward the heat exchanger unit <NUM>, the air conditioning system <NUM> may be configured to add such slight supply air volume to total airflow volume. The air conditioning system <NUM> may alternatively be configured not to add such slight supply air volume to the total airflow volume.

The main controller <NUM> totals supply air volume transmitted from all the fan units <NUM> to calculate total airflow volume through the utilization heat exchanger <NUM>. The main controller <NUM> calculates temperature of air sucked to the heat exchanger unit <NUM> with reference to the suction temperature sensor <NUM> of the heat exchanger unit <NUM>. The main controller <NUM> requests, to the heat source controller <NUM> of the heat source unit <NUM>, necessary refrigerant circulation volume calculated from the total airflow volume of air passing the utilization heat exchanger <NUM> and the air temperature. The heat source controller <NUM> of the heat source unit <NUM> changes the operating frequency of the compressor <NUM> to change the refrigerant circulation volume in accordance with the request from the main controller <NUM>.

The air conditioning system <NUM> in normal operation controls differently between a case where the total airflow volume is equal to or more than a lower limit value and a case where the total airflow volume is less than the lower limit value. Description is made to the case where control is changed in accordance with the lower limit value, although the air conditioning system <NUM> refers to a value for change in control, which is not limited to the lower limit value. The air conditioning system <NUM> can be configured to change control between a case where the total airflow volume is equal to or more than a predetermined value and a case where the total airflow volume is less than the predetermined value. As repeated description, the predetermined value may adopt the lower limit value or may adopt a value other than the lower limit value.

When predetermined time elapses after activation and the system comes into a normal operation state, the main controller <NUM> determines whether or not the total airflow volume is equal to or more than the lower limit value. The lower limit value will be described later in terms of setting thereof. When the total airflow volume is equal to or more than the lower limit value, the main controller <NUM> controls the air conditioning system <NUM> in the following manner.

When predetermined time elapses after activation and the system comes into the normal operation state, the fan controllers <NUM> are each configured to recalculate individual supply air volume at predetermined intervals. Such recalculation includes calculating an air conditioning load with reference to indoor air temperature sensed by the remote controller <NUM>, in accordance with a situation that the indoor air temperature adjacent to each of the blow-out port units <NUM> "approaches", "is largely different from" the set temperature, or the like, and each of the fan controllers <NUM> corrects the set airflow volume. Each of the fan units <NUM> transmits corrected supply air volume thus obtained to the main controller <NUM>. The main controller <NUM> may alternatively be configured to execute calculation on correction of set airflow volume. The main controller <NUM> recalculates supply air volume transmitted from the plurality of fan controllers <NUM> at each interval to obtain total airflow volume, and requests, to the heat source controller <NUM> of the heat source unit <NUM>, when the total airflow volume is equal to or more than the lower limit value, necessary refrigerant circulation volume calculated from the total airflow volume of air passing the utilization heat exchanger <NUM> and the air temperature at each interval. The heat source controller <NUM> of the heat source unit <NUM> changes the operating frequency of the compressor <NUM> to change the refrigerant circulation volume in accordance with the request from the main controller <NUM>.

When the total airflow volume is less than the lower limit value, the main controller <NUM> calculates a shortfall as a difference between the calculated total airflow volume and the lower limit value. The main controller <NUM> allocates the shortfall to the plurality of fan units <NUM> in accordance with a preliminarily determined airflow volume distribution rule. When the shortfall is allocated to the plurality of fan units <NUM>, supply air volume matching the shortfall may be allocated or supply air volume equal to or more than the shortfall may be allocated because the total airflow volume has only to be equal to or more than the lower limit value.

Assume an exemplary case where the lower limit value is <NUM><NUM>/min, and the main controller <NUM> has requests for <NUM><NUM>/min from the fan controller <NUM> of the fan unit 30a, <NUM><NUM>/min from the fan controller <NUM> of the fan unit 30b, <NUM><NUM>/min from the fan controller <NUM> of the fan unit 30c, and <NUM><NUM>/min from the fan controller <NUM> of the fan unit 30d. In this case, the main controller <NUM> calculates total airflow volume of <NUM><NUM>/min > <NUM><NUM>/min, and determines that the total airflow volume is more than the lower limit value.

When the fan controller <NUM> of the fan unit 30c subsequently receives a command to stop blowing from the remote controller <NUM>, the fan controller <NUM> of the fan unit 30c changes the request from <NUM><NUM>/min to <NUM><NUM>/min. The total airflow volume then decreases from <NUM><NUM>/min to <NUM><NUM>/min. The main controller <NUM> thus determines that there is commanded to change the total airflow volume to be equal to or less than the lower limit value.

In an exemplary case of having determined that there is commanded to change to be equal to or less than the lower limit value, the main controller <NUM> may allocate the shortfall equally to the fan units <NUM> in operation. In the above case, <NUM> (= <NUM> - <NUM>) m<NUM>/min is allocated to the fan unit 30a by <NUM><NUM>/min and is allocated to the fan unit 30d by <NUM><NUM>/min, so that the fan unit 30a is changed to <NUM><NUM>/min and the fan unit 30d is changed to <NUM><NUM>/min.

In another exemplary case of having determined that there is commanded to change to be equal to or less than the lower limit value, the main controller <NUM> may allocate the shortfall equally to all the fan units <NUM>. In the above case, <NUM> (= <NUM> - <NUM>) m<NUM>/min is allocated to each of the fan units 30a to 30d by <NUM><NUM>/min, so that the fan unit 30a is changed to <NUM><NUM>/min, the fan unit 30b is changed to <NUM><NUM>/min, the fan unit 30c is changed to <NUM><NUM>/min, and the fan unit 30d is changed to <NUM><NUM>/min.

The lower limit value of the total airflow volume of the air conditioning system <NUM> is determined by the main controller <NUM> in accordance with heat exchanger temperature or the like. At high heat exchanger temperature during cooling operation, the main controller <NUM> determines that the heat source unit <NUM> has insufficient heat energy supply capacity and sets a high lower limit value of the total airflow volume. In comparison to such a case, at low heat exchanger temperature during cooling operation, the main controller <NUM> determines that the heat source unit <NUM> has sufficient heat energy supply capacity and sets a lower limit value of the total airflow volume less than the lower limit value in the above case. The lower limit value may be specifically determined through at least one of an actual test and a simulation of the air conditioning system <NUM>.

Assume that, in the distribution flow path including the duct 20a, the fan unit 30a, and the blow-out port unit 70a, a normal airflow travels from the heat exchanger unit <NUM> toward the blow-out port <NUM> whereas an abnormal airflow as an air backflow travels from the blow-out port <NUM> toward the heat exchanger unit <NUM>. Similarly in each of the distribution flow paths including the ducts 20b to 20d, the fan units 30b to 30d, and the blow-out port units 70b to 70d, an air backflow travels from the blow-out port <NUM> toward the heat exchanger unit <NUM>. The single differential pressure sensor <NUM> provided at each of the fan units 30a to 30d has a detection result transmitted to the main controller <NUM> via the fan controller <NUM>.

The main controller <NUM> determines that an airflow is normal in a case where the exhaust port <NUM> is lower in air pressure than the intake port <NUM> of each of the fan units 30a to 30d, and determines that there is an air backflow in another case where the exhaust port <NUM> is higher in air pressure than the intake port <NUM> of each of the fan units 30a to 30d.

The main controller <NUM> eliminates an air backflow in cooperation with the fan units <NUM>. Specifically, the main controller <NUM> senses the fan unit <NUM> connected to the distribution flow path having an air backflow. The main controller <NUM> transmits a command to increase the rotation speed of the fan motor <NUM> to the fan controller <NUM> of the fan unit <NUM> on the distribution flow path having the air backflow. In an exemplary case where the fan motor <NUM> is stopped, the main controller <NUM> transmits a command to start driving at a preliminarily determined rotation speed. In another case where the fan motor <NUM> is rotating at low speed, the main controller <NUM> transmits a command to further increase the rotation speed of the fan motor <NUM>.

When the wind direction plate <NUM> is configured to change air resistance, the wind direction plate <NUM> may alternatively be adopted to eliminate an air backflow. When the fan motor <NUM> is stopped, the wind direction plate <NUM> of the blow-out port unit <NUM> having an air backflow may be fully closed. When the fan motor <NUM> is rotating at low speed, the main controller <NUM> may be configured to transmit a command to further increase the rotation speed of the fan motor <NUM> as well as increase the air resistance at the wind direction plate <NUM>.

Still alternatively, the distribution flow path may be provided therein with a backflow preventing damper that is fully closed only by force of an air backflow. In this case, backflow prevention can be achieved even without any command from the main controller <NUM>.

The first embodiment described above refers to the case where the ducts <NUM> are connected directly to the heat exchanger unit <NUM>. The ducts <NUM> may alternatively be connected indirectly to the heat exchanger unit <NUM>. For example, the ducts <NUM> and the heat exchanger unit <NUM> may alternatively interpose an attachment having a plurality of air outlet ports for connection of the ducts <NUM> to the heat exchanger unit <NUM>. There may be prepared plural types of attachments different in the number of connectable ducts <NUM>, to enable change in the number of the ducts <NUM> connectable to the heat exchanger unit <NUM> of an identical type.

The first embodiment described above refers to the case where the single blow-out port unit <NUM> is connected to the single fan unit <NUM>. Alternatively, a plurality of blow-out port units <NUM> may be connected to the single fan unit <NUM>. That is, the single fan unit <NUM> may be provided with a plurality of air outlet <NUM>. In this case, each of the blow-out port units <NUM> may be provided with a single remote controller <NUM>, to connect a plurality of remote controllers <NUM> to each of the fan units <NUM>.

The first embodiment described above refers to the case where a wall between the rooms RA1 and RA2 is provided with a vent hole <NUM> and the single blow-in port <NUM> is provided. The blow-in port <NUM> is not limited to one in terms of the number thereof, but there may alternatively be provided a plurality of blow-in ports <NUM>. Furthermore, a plurality of blow-in ports <NUM> may be provided at the identical room RA1 or may be provided at both of the different rooms RA1 and RA2. There is no need to provide any vent hole <NUM> when the blow-in port <NUM> is provided at each of the rooms RA1 and RA2.

The fan unit <NUM> connected to the second end <NUM> of the duct <NUM> having the first end <NUM> connected to the heat exchanger unit <NUM> may further be connected with another duct <NUM> and another fan unit <NUM>.

For example, a single distribution flow path may be connected in series with a plurality of fan units <NUM>. According to an exemplary aspect of such connection, two ducts <NUM>, two fan units <NUM>, and a single blow-out port unit <NUM> are connected in series in the order of the heat exchanger unit <NUM>, the duct <NUM>, the fan unit <NUM>, the duct <NUM>, the fan unit <NUM>, and the blow-out port unit <NUM>. Provision of a plurality of power sources on a single distribution flow path enables setting a longer distance from the heat exchanger unit <NUM> to the blow-out port <NUM> in comparison to a case of providing only one of the power sources configured similarly.

The first embodiment described above refers to the case where the single heat exchanger unit <NUM> is connected to the single heat source unit <NUM>. Connection between the heat source unit <NUM> and the heat exchanger unit <NUM> is not limited to such a connection aspect. Alternatively, a plurality of heat exchanger units <NUM> may be connected to the single heat source unit <NUM>. Still alternatively, a plurality of heat source units <NUM> may be connected to a plurality of heat exchanger units <NUM>. According to these connection aspects, the heat exchanger units <NUM> may be each provided with a flow rate adjuster configured to adjust a flow rate of a refrigerant flowing in the utilization heat exchanger <NUM>. Examples of the flow rate adjuster include a flow rate control valve having a variable valve opening degree. When the single refrigerant circuit <NUM> includes a plurality of heat exchanger units <NUM> and the refrigerant circuit <NUM> is provided therein with a refrigerant system configured to circulate a refrigerant in a specific one of the heat exchanger units <NUM>, the specific heat exchanger unit <NUM> has the lower limit value of airflow volume through the utilization heat exchanger <NUM>, and the lower limit value may be set to vary in accordance with a parameter influencing a state or circulation volume of a refrigerant circulating in the refrigerant system.

The first embodiment described above refers to the case where the compressor <NUM> in the heat source unit <NUM> is of the type having a variable rotation speed. The compressor <NUM> in the heat source unit <NUM> may alternatively be of a type having a nonvariable rotation speed.

The first embodiment described above refers to the case where the air conditioning system <NUM> is configured to switch between cooling operation and heating operation. The technical concept according to the first embodiment is also applicable to an air conditioning system dedicated to cooling operation or heating operation.

The first embodiment described above refers to the case where the heat source unit <NUM> and the heat exchanger unit <NUM> are connected to constitute the refrigeration cycle apparatus allowing the refrigerant to flow to the utilization heat exchanger <NUM>. The heat source unit <NUM> is not limitedly connected to the heat exchanger unit <NUM> to constitute the refrigeration cycle apparatus. The heat source unit configured to supply the utilization heat exchanger <NUM> with heat energy may alternatively be configured to supply a heating medium such as at least one of warm water and cold water.

When the heat source unit is configured to supply a heating medium to the utilization heat exchanger <NUM>, the heat exchanger unit <NUM> may be provided with a flow rate adjuster configured to adjust a flow rate of the heating medium flowing to the utilization heat exchanger <NUM>.

When the heat exchanger unit <NUM> is connected to the heat source unit configured to supply the heating medium, a single heat source unit may be connected with a plurality of heat exchanger units <NUM>.

The first embodiment described above refers to the case where the main controller <NUM> requests, upon activation, the refrigerant circulation volume necessary for the refrigerant circuit <NUM>, calculated from the obtained total airflow volume of air passing the utilization heat exchanger <NUM> and the calculated temperature of air sucked into the heat exchanger unit <NUM>. The necessary refrigerant circulation volume requested by the main controller <NUM> is determined in a manner not limited to the above.

For example, the air conditioning system <NUM> may be configured as follows. Upon activation, the main controller <NUM> totals supply air volume transmitted from all the fan units <NUM> to calculate total airflow volume through the utilization heat exchanger <NUM>. The main controller <NUM> stores, in an internal memory or the like, an airflow volume table indicating a relation between total airflow volume and necessary refrigerant circulation volume. The main controller <NUM> selects airflow volume closest to the calculated total airflow volume, from among airflow volume included in the airflow volume table. The main controller <NUM> requests, to the heat source controller <NUM>, refrigerant circulation volume corresponding to the total airflow volume selected from the airflow volume table. As to a difference between the airflow volume selected from the airflow volume table and the total airflow volume, the air conditioning system <NUM> may be configured such that the main controller <NUM> transmits a command to the fan controller <NUM> to change supply air volume correspondingly to the difference in each of the fan units <NUM>.

The air conditioning system <NUM> may alternatively be configured as follows. Upon activation, the main controller <NUM> receives set temperature of the remote controller <NUM> via the fan controller <NUM>. The main controller <NUM> further receives indoor air temperature detected by the remote controller <NUM>, indoor air temperature calculated from a detection value of the suction temperature sensor <NUM>, or indoor air temperature from an indoor temperature sensor capable of transmitting indoor air temperature to the main controller <NUM>. The main controller <NUM> calculates an entire air conditioning load of the air conditioning system <NUM> from the set temperature and the indoor air temperature thus received. The main controller <NUM> calculates total airflow volume and necessary refrigerant circulation volume from the air conditioning load thus calculated. The main controller <NUM> calculates individual supply air volume of each of the fan units <NUM> by multiplying the total airflow volume and a ratio of the air conditioning load of each of the fan units <NUM>, and transmits commands to the plurality of fan controllers <NUM>. The air conditioning system <NUM> may be configured such that each of the fan controllers <NUM> individually adjusts in accordance with the individual supply air volume commanded by the main controller <NUM>.

As to the air conditioning system <NUM> according to the first embodiment, description is made to the case where total airflow volume is determined principally and the main controller <NUM> controls to follow a condition for the refrigerant of the heat source unit <NUM>. The air conditioning system <NUM> may alternatively be configured to principally determine a condition for the refrigerant of the heat source unit <NUM> and determine total airflow volume in accordance with the condition.

For example, the air conditioning system <NUM> is configured such that the heat source controller <NUM> controls at least one of the operating frequency of the compressor <NUM> and the opening degree of the expansion valve <NUM>. In the air conditioning system <NUM> thus configured, the heat source controller <NUM> acquires information on the current total airflow volume of air passing the utilization heat exchanger <NUM>. The heat source controller <NUM> transmits, to the main controller <NUM>, that the current total airflow volume needs to be increased or decreased in accordance with information on at least one of the operating frequency of the compressor <NUM> and the opening degree of the expansion valve <NUM>. The main controller <NUM> receives a command to increase or decrease the airflow volume from the heat source controller <NUM>, calculates appropriate proportions of increase or decrease in airflow volume of the plurality of fan units <NUM> for energy suppression in the entire system, and commands the fan units <NUM>.

In the air conditioning system <NUM> according to the first embodiment, the operating frequency of the compressor <NUM> is changed to adjust the refrigerant circulation volume of the refrigerant circuit <NUM>. Control of the refrigerant circulation volume in the air conditioning system <NUM> is, however, not limited to control of the operating frequency of the compressor <NUM>. For example, the refrigerant circulation volume of the refrigerant circuit <NUM> may be controlled to be adjusted by adjusting the operating frequency of the compressor <NUM> as well as the opening degree of the expansion valve <NUM>. Alternatively, the refrigerant circulation volume of the refrigerant circuit <NUM> may be controlled to be adjusted by adjusting the opening degree of the expansion valve <NUM>.

The above first embodiment provides the lower limit value of the total airflow volume determined in accordance with the heat exchanger temperature of the utilization heat exchanger <NUM>. There may alternatively be referred to condensation temperature (TC), evaporation temperature (TE), a degree of superheating (SH), or a degree of subcooling (SC). The degree of superheating can be calculated from inlet temperature and outlet temperature of the utilization heat exchanger <NUM>, or inlet pressure and outlet temperature of the utilization heat exchanger <NUM>. The degree of subcooling can be calculated from inlet temperature and outlet temperature of the utilization heat exchanger <NUM>, or inlet pressure and outlet temperature of the utilization heat exchanger <NUM>.

The lower limit value of the total airflow volume may be a preliminarily determined and fixed value. When the lower limit value is preliminarily determined as <NUM><NUM>/min, the main controller <NUM> controls such that the total airflow volume constantly does not become less than the lower limit value <NUM><NUM>/min.

The air conditioning system <NUM> may alternatively be configured to have, for cooling operation, the lower limit value of the total airflow volume exemplarily determined in accordance with the degree of superheating, the current total airflow volume, and suction temperature of air sucked into the heat exchanger unit <NUM>. The air conditioning system <NUM> may still alternatively be configured to have, for heating operation, the lower limit value of the total airflow volume determined in accordance with the degree of subcooling, the current total airflow volume, and suction temperature of air sucked into the heat exchanger unit <NUM>. The air conditioning system <NUM> may still alternatively be configured to have the lower limit value of the total airflow volume determined in accordance with the refrigerant circulation volume (e.g. the operating frequency of the compressor <NUM>), the evaporation temperature (TE), as well as suction temperature and sucked airflow volume of air sucked to the heat exchanger unit <NUM>. The air conditioning system <NUM> may still alternatively be configured to have the lower limit value of the total airflow volume determined in accordance with the current airflow volume and excessive or insufficient airflow volume calculated from a dried or wetted degree of the refrigerant having passed the utilization heat exchanger <NUM>. The air conditioning system <NUM> may still alternatively be configured to have the lower limit value of the total airflow volume determined in accordance with refrigerant pressure and refrigerant temperature at the outlet port of the utilization heat exchanger <NUM>.

(<NUM>-<NUM>-<NUM>)
The first embodiment exemplifies the fan motors <NUM> having a variable rotation speed, as the plurality of actuators configured to change individual supply air volume of conditioned air sucked from the heat exchanger unit <NUM> through the plurality of ducts <NUM> and supplied to the plurality of air outlet <NUM> in the air conditioning target space SA. The actuators are not limited to the fan motors <NUM>, and examples of the actuators include a drive motor <NUM> of a damper <NUM> depicted in <FIG>. The fan motor <NUM> of the fan <NUM> depicted in <FIG> may of a type having a variable rotation speed as in the first embodiment, or may of a type having a nonvariable rotation speed. When the fan motor <NUM> is of the type having a nonvariable rotation speed, supply air volume (airflow volume) from the fan unit <NUM> to the blow-out port unit <NUM> is changed only with use of the damper <NUM>. In contrast, when the fan motor <NUM> is of the type having a variable rotation speed, the supply air volume (airflow volume) from the fan unit <NUM> to the blow-out port unit <NUM> is changed through change in opening degree of the damper <NUM> in combination with change in the rotation speed of the fan motor <NUM>.

The main controller <NUM> eliminates an air backflow in cooperation with the fan units <NUM>. For elimination of an air backflow, the main controller <NUM> initially detects the fan unit <NUM> connected to the distribution flow path having the air backflow. When the fan unit <NUM> is configured to adjust supply air volume only with use of the damper <NUM>, the main controller <NUM> transmits a command to change the opening degree of the damper <NUM> to the fan controller <NUM> of the fan unit <NUM> on the distribution flow path having the air backflow. A command to fully close the damper <NUM> is transmitted in an exemplary case where the fan unit <NUM> having the air backflow is not in operation. There is normally caused no air backflow when the fan motor <NUM> constantly rotates to blow and air blows in accordance with the opening degree of the damper <NUM>. Upon occurrence of an air backflow in such a case, the main controller <NUM> notifies a user of abnormality occurrence with use of the remote controller <NUM> or the like.

When the fan unit <NUM> is configured to adjust supply air volume by means of both the rotation speed of the fan motor <NUM> and the opening degree of the damper <NUM>, the main controller <NUM> transmits a command to change at least one of the rotation speed of the fan motor <NUM> and the opening degree of the damper <NUM> to the fan controller <NUM> of the fan unit <NUM> on the distribution flow path having the air backflow. A command to fully close the damper <NUM> is transmitted in an exemplary case where the fan unit <NUM> having the air backflow is not in operation. In another case where the fan motor <NUM> is rotating at low speed, the main controller <NUM> transmits a command to further increase the rotation speed. When the fan motor <NUM> is rotating at low speed, the main controller <NUM> may alternatively be configured to transmit a command to decrease the opening degree of the damper <NUM> as well as increase the rotation speed of the fan motor <NUM>.

The first embodiment described above refers to the case where the differential pressure sensor <NUM> is adopted as a detector configured to detect an air backflow. However, the detector configured to detect an air backflow is not limited to the differential pressure sensor <NUM>. Examples of the detector also include a wind speed sensor having directivity. When the differential pressure sensor <NUM> is replaced with a wind direction sensor having directivity, the wind direction sensor is exemplarily disposed at the fan unit <NUM> and is connected to the fan controller <NUM>. With use of the wind direction sensor having directivity, the main controller <NUM> can detect that air flows in a normal direction when wind speed in a positive direction is indicated, and that an air backflow occurs when wind speed in an opposite negative direction is indicated. The examples of the detector also include a wind speed sensor having no directivity. When a plurality of wind speed sensors having no directivity detects wind speed distribution and the wind speed distribution occurs with a backflow, the main controller <NUM> can determine that there occurs a backflow.

The first embodiment described above refers to the configuration for detection of differential pressure within a determined section with use of the differential pressure sensor <NUM> (airflow volume sensing unit). The configuration for sensing of airflow volume is not limited to the above. For example, airflow volume can be sensed exemplarily by sensing differential pressure between in front of and behind the fan <NUM> of the fan unit <NUM> with use of the differential pressure sensor, and calculating airflow volume with use of the main controller <NUM> or the fan controller <NUM> from a differential pressure characteristic between in front of and behind the fan <NUM>. The differential pressure sensor functions as the airflow volume sensing unit also in this case. For example, wind speed at a specific position can be sensed with use of the wind speed sensor, and the main controller <NUM> or the fan controller <NUM> can calculate airflow volume from a wind speed characteristic at the specific position. The wind speed sensor functions as the airflow volume sensing unit in this case. For example, internal pressure displacement can be sensed with use of a pressure sensor, and the main controller <NUM> or the fan controller <NUM> can calculate airflow volume with comparison between internal pressure displacement during predefined airflow volume and the pressure displacement thus sensed. The pressure sensor functions as the airflow volume sensing unit in this case. For example, with use of operation current of the fan <NUM>, the main controller <NUM> or the fan controller <NUM> can be configured to calculate airflow volume from a workload of the fan motor <NUM>. A device configured to sense operation current functions the airflow volume sensing unit in this case.

The first embodiment described above refers to the exemplary case where the main controller <NUM> calculates refrigerant circulation volume and transmits, to the heat source controller <NUM>, a request for change in operating frequency of the compressor <NUM>, and the heat source controller <NUM> controls the operating frequency of the compressor <NUM>. The air conditioning system <NUM> may alternatively be configured such that the main controller <NUM> controls at least one of the operating frequency of the compressor <NUM> and the opening degree of the expansion valve <NUM>.

The first embodiment described above exemplifies the case where the main controller <NUM> is provided at the heat exchanger unit <NUM>. However, the main controller <NUM> is provided at a place not limited to the heat exchanger unit <NUM>. The main controller <NUM> may be exemplarily at the fan unit <NUM>.

(<NUM>-<NUM>)
The main controller <NUM> in the air conditioning system <NUM> controls the fan motors <NUM>, the drive motors <NUM> of the dampers <NUM>, or the wind direction plate motors <NUM> of the wind direction plates <NUM>, as the plurality of actuators of the plurality of fan units <NUM>, such that the airflow volume through the utilization heat exchanger <NUM> satisfies a predetermined condition. This configuration inhibits malfunction of the air conditioning system <NUM> by means of the airflow volume through the utilization heat exchanger <NUM>.

(<NUM>-<NUM>)
The air conditioning system <NUM> detects airflow volume of each of the totally four distribution flow paths including the distribution flow path constituted by the duct 20a, the fan unit 30a, and the blow-out port <NUM> of the blow-out port unit 70a, and the three distribution flow paths similarly constituted by the ducts 20b to 20d, the fan units 30b to 30d, and the air outlet <NUM> of the blow-out port units 70b to 70d. The main controller <NUM> totals the airflow volume thus detected, and controls the fan motors <NUM>, the drive motors <NUM>, or the wind direction plate motors <NUM> as the actuators in accordance with total airflow volume thus obtained.

(<NUM>-<NUM>)
More specifically, the main controller <NUM> controls the numbers of revolutions of the plurality of fan motors <NUM> with reference to the plurality of airflow volume of the plurality of distribution flow paths detected by differential pressure sensors <NUM> or the wind speed sensors as the plurality of airflow volume sensing units. This configuration facilitates control such that the airflow volume through the utilization heat exchanger <NUM> satisfies the predetermined condition.

(<NUM>-<NUM>)
As described in the modification examples, the main controller <NUM> controls to change the plurality of airflow volume by changing the opening degrees of the plurality of dampers <NUM> with use of the drive motors <NUM> as the plurality of opening-closing devices, with reference to the detection values of the plurality of airflow volume of the plurality of distribution flow paths detected by the plurality of differential pressure sensors <NUM> or the wind speed sensors. The main controller <NUM> can thus easily control such that the airflow volume through the utilization heat exchanger <NUM> satisfies the predetermined condition.

(<NUM>-<NUM>)
The predetermined condition of the air conditioning system <NUM> is to set the airflow volume through the utilization heat exchanger <NUM> to be equal to or more than the lower limit value. This configuration inhibits malfunction of the air conditioning system <NUM>, which is caused by insufficient heat exchange in the utilization heat exchanger <NUM> due to the airflow volume through the utilization heat exchanger <NUM> being less than the lower limit value.

(<NUM>-<NUM>)
The heat source unit <NUM> is a heat source device including the compressor <NUM> and constituting the refrigerant circuit <NUM> along with the utilization heat exchanger <NUM>. The refrigerant circuit <NUM> achieves the vapor compression refrigeration cycle. The main controller <NUM> is connected to the heat source controller <NUM>, and links control of the fan motors <NUM>, the drive motors <NUM> of the dampers <NUM>, or the wind direction plate motors <NUM> of the wind direction plates <NUM> with control of the refrigerant circuit <NUM>. The air conditioning system <NUM> can thus appropriately control the airflow volume through the utilization heat exchanger <NUM> by means of the fan motors <NUM>, the drive motors <NUM>, or the wind direction plate motors <NUM> as the plurality of actuators in accordance with a state of the refrigerant circuit <NUM>, to achieve efficient operation.

(<NUM>-<NUM>)
In the air conditioning system <NUM>, the lower limit value of the airflow volume through the utilization heat exchanger <NUM> is set to vary in accordance with the parameter of the heat source unit <NUM> influencing the state or the circulation volume of the refrigerant circulating in the refrigerant circuit <NUM>. The air conditioning system <NUM> thus causes the utilization heat exchanger <NUM> to exchange heat suitably for the state or the circulation volume of the refrigerant circulating in the refrigerant circuit <NUM> to achieve an appropriate state of the refrigerant passing the utilization heat exchanger <NUM> and inhibit malfunction of the heat source unit <NUM> as the heat source device.

(<NUM>-<NUM>)
When the lower limit value of the airflow volume through the utilization heat exchanger <NUM> is set to vary in accordance with a value relevant to the circulation volume of the refrigerant in the refrigerant circuit <NUM>, the air conditioning system causes the utilization heat exchanger <NUM> to exchange heat at the lower limit value of the appropriate airflow volume suitable for the circulation volume of the refrigerant circulating in the refrigerant circuit <NUM>, to inhibit malfunction of the heat source unit <NUM> as the heat source device.

(<NUM>-<NUM>)
The lower limit value of the airflow volume is set to vary in accordance with the parameter of the heat source unit <NUM> as the heat source device influencing the state or the circulation volume of the refrigerant circulating in the refrigerant circuit <NUM>. The air conditioning system <NUM> causes the utilization heat exchanger <NUM> to exchange heat suitably for the state or the circulation volume of the refrigerant circulating in the refrigerant circuit <NUM>, to suppress energy consumption of the air conditioning system <NUM>. Examples of the parameter of the heat source unit <NUM> for suppression in energy consumption of the air conditioning system <NUM> through change in lower limit value of the airflow volume through the utilization heat exchanger <NUM> include the condensation temperature of the refrigerant circuit <NUM>, the evaporation temperature of the refrigerant circuit <NUM>, the heat exchanger temperature of the utilization heat exchanger <NUM>, the operating frequency of the compressor <NUM>, combination of inlet temperature and outlet temperature of the utilization heat exchanger <NUM>, and combination of inlet pressure and the outlet temperature of the utilization heat exchanger <NUM>.

(<NUM>-<NUM>)
When the remote controller <NUM> transmits a command to stop blowing or further decrease the airflow volume for at least one of the fan units <NUM> and the airflow volume through the utilization heat exchanger <NUM> is calculated to be less than the lower limit value, the air conditioning system <NUM> may alternatively be configured such that the main controller <NUM> controls to allocate the airflow volume also to the fan unit <NUM> commanded to stop blowing in the plurality of fan units <NUM>. Such control can suppress increase in airflow volume per fan unit and can suppress a partial gap of the indoor air temperature from the set temperature in the air conditioning target space SA.

(<NUM>-<NUM>)
The air conditioning system <NUM> may still alternatively be configured such that the main controller <NUM> controls to allocate the airflow volume to each operating one of the plurality of fan units <NUM>. When the main controller <NUM> controls in this manner, there is no need to operate the fan unit <NUM> commanded to stop in the plurality of fan units <NUM>. This configuration reliably stops any one of the fan units <NUM> for a place desired to stop air conditioning, and inhibits the air conditioning system <NUM> from operating not in accordance with a user request.

In the air conditioning system <NUM> according to the first embodiment, the main controller <NUM> controls the plurality of actuators in accordance with the plurality of commands on supply air volume of the plurality of fan units <NUM>. Such a mode is not limited to the mode of the air conditioning system <NUM> according to the first embodiment. The air conditioning system <NUM>, in which the main controller <NUM> controls the plurality of actuators in accordance with the plurality of commands on supply air volume of the plurality of fan units <NUM>, may alternatively be configured as in the second embodiment.

In the air conditioning system according to the second embodiment, the plurality of fan controllers as a plurality of sub controllers receives the plurality of commands transmitted from the main controller. In the air conditioning system according to the second embodiment, each of the fan controllers controls at least one of the actuators in accordance with at least one of the commands.

Specifically, exemplarily described is the case where the air conditioning system <NUM> according to the second embodiment includes the configurations depicted in <FIG> similarly to the air conditioning system <NUM> according to the first embodiment. The second embodiment relates to the case where the air conditioning system <NUM> depicted in <FIG> changes supply air volume by means of the fan motors <NUM>, whereas the dampers <NUM> or the wind direction plates <NUM> are not involved in change in supply air volume.

Similarly to the main controller <NUM> according to the first embodiment, the main controller <NUM> according to the second embodiment calculates necessary supply air volume to be blown out of the fan units <NUM>, from the blow-out temperature detected by the blow-out temperature sensors <NUM> and the set temperature. Specifically, the main controller <NUM> exemplarily calculates supply air volume of each of the fan units 30a to 30d from the temperature difference between the indoor air temperature adjusted by the corresponding one of the fan units 30a to 30d and the set temperature, as well as the blowing air temperature. The main controller <NUM> determines, as commands to be transmitted to the fan units 30a to 30d, the calculated supply air volume (target supply air volume) of the fan units 30a to 30d.

The main controller <NUM> transmits, to the plurality of fan controllers <NUM>, the plurality of supply air volume thus calculated as the target supply air volume. In other words, the main controller <NUM> transmits the plurality of commands to the plurality of fan controllers <NUM> configured to control the fan units 30a to 30d. For example, the main controller <NUM> transmits the target supply air volume of the fan unit 30a to the fan controller <NUM> attached to the fan unit 30a. The target supply air volume of the fan unit 30a corresponds to the command on supply air volume of the fan unit <NUM>. The fan controller <NUM> of the fan unit 30a controls the rotation speed of the fan motor 33a so as to approach the supply air volume to the target supply air volume. Similarly, the main controller <NUM> transmits the target supply air volume of the fan units 30b to 30d to the fan controllers <NUM> attached to the fan units 30b to 30d, respectively. The fan controllers <NUM> of the fan units 30b to 30d control the fan motors 33b to 33d so as to approach the supply air volume to the target supply air volume.

In more detail, the fan units 30a to 30d according to the second embodiment each include a wind speed sensor instead of and at a position of the differential pressure sensor <NUM> as the airflow volume sensing unit configured to sense airflow volume through the unit. The airflow volume sensing unit is not limited to the wind speed sensor. Examples of the airflow volume sensing unit include the differential pressure sensor <NUM>. For example, the fan controller <NUM> of the fan unit 30a compares wind speed of the fan unit 30a with target airflow volume (target supply air volume). The fan controller <NUM> of the fan unit 30a increases the rotation speed of the fan motor 33a in a case where airflow volume through the fan unit 30a is less than the target airflow volume, to increase the airflow volume (supply air volume) of the fan unit 30a so as to approach the target airflow volume. The fan controller <NUM> decreases the rotation speed of the fan motor 33a in another case where the airflow volume through the fan unit 30a is more than the target airflow volume, to decrease the airflow volume (supply air volume) of the fan unit 30a so as to approach the target airflow volume. Description is made to the case where the fan controller <NUM> is attached to the fan unit <NUM>. The fan controller <NUM> may, however, not be attached to the fan unit <NUM>.

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.

Claim 1:
An air conditioning system (<NUM>) comprising a heat exchanger unit (<NUM>) having a utilization heat exchanger (<NUM>) and configured to generate conditioned air through heat exchange in the utilization heat exchanger and supply an air conditioning target space with the conditioned air through a plurality of distribution flow paths communicating with the heat exchanger unit,
each of the distribution flow paths including a duct (<NUM>, 20a to 20d) connected to the heat exchanger unit and provided for distribution of the conditioned air, and a fan unit (<NUM>, 30a to 30d) provided correspondingly to the duct and configured to supply the air conditioning target space with the conditioned air from the heat exchanger unit through the ducts,
wherein
each of the distribution flow paths further including an actuator (<NUM>, <NUM>, <NUM>) configured to individually change supply air volume of the conditioned air supplied to the air conditioning target space, and
wherein the air conditioning system further comprising a main controller (<NUM>) configured to control the actuators such that airflow volume through the utilization heat exchanger satisfies a predetermined condition, characterized in that
at least either the ducts or the fan units each include an airflow volume sensing unit (<NUM>),
the main controller is configured to total airflow volume through the distribution flow paths detected by the airflow volume sensing units and control the actuators such that a total satisfies the predetermined condition,
the actuators are fan motors (<NUM>) of the fan units, and
the main controller controls numbers of revolutions of the fan motors in accordance with values of the airflow volume sensing units.