초록 ▼

A low-cost and highly-efficient air-conditioning system including an AHU using refrigerant of a heat pump cycle as a heat source, and capable of reducing an on/off cycle operation of compressors at a time of a low load, the system including: a plurality of outdoor units; an air handling unit; a plur

A low-cost and highly-efficient air-conditioning system including an AHU using refrigerant of a heat pump cycle as a heat source, and capable of reducing an on/off cycle operation of compressors at a time of a low load, the system including: a plurality of outdoor units; an air handling unit; a plurality of independent heat pump cycles formed by connecting the plurality of outdoor units and the air handling unit by refrigerant pipes, each of the plurality of independent heat pump cycles including a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger; and a number control unit controlling, to satisfy a capacity demand corresponding to an air-conditioning load, based on a particular frequency range associated with the compressor, in which a certain compressor efficiency or more is obtained, a number of the compressors in operation and operating frequencies of the respective compressors in operation.

대표청구항 ▼

1. An air-conditioning system, comprising: a plurality of outdoor units each including a compressor, a pressure-reducing device, and an outdoor heat exchanger;an air handling unit including a passage for exchanging air inside and outside a construction to perform ventilation, and an indoor heat exch

1. An air-conditioning system, comprising: a plurality of outdoor units each including a compressor, a pressure-reducing device, and an outdoor heat exchanger;an air handling unit including a passage for exchanging air inside and outside a construction to perform ventilation, and an indoor heat exchanger through which the air inside the passage flows;refrigerant pipes;a plurality of independent heat pump cycles each being independently formed by connecting each of the plurality of outdoor units and the air handling unit by refrigerant pipes, each of the plurality of independent heat pump cycles including the compressor, the indoor heat exchanger, the pressure-reducing device, and the outdoor heat exchanger; anda number control unit configured to: in response to receiving a capacity demand corresponding to an air-conditioning load, compute a required total operating frequency for the plurality of compressors which are connected by the refrigerant pipes, that satisfies the capacity demand corresponding to the air-conditioning load,determine, based on the required total operating frequency, one predetermined frequency range of a plurality of predetermined frequency ranges associated with each of the compressors in operation, wherein each predetermined frequency range of the plurality of predetermined frequency ranges is defined to achieve at least a predetermined compressor efficiency, and each predetermined frequency range has corresponding number control information, wherein each corresponding number control information defines a control of operating frequencies of the plurality of compressors based on a number of compressors in operation and a predefined high efficiency frequency range for each of the compressors, andcontrol the number of the compressors to operate and an operating frequency of each of the compressors in operation based on the control defined by the number control information corresponding to the one predetermined frequency range which is determined. 2. The air-conditioning system of claim 1, wherein the number control unit is further configured to control the number of the compressors to operate and the operating frequency of each of the compressors in operation so that a sum of the operating frequency of each of the compressors in operation becomes the required total operating frequency. 3. The air-conditioning system of claim 2, wherein the number control unit has number control information that defines a relationship among a total operating frequency, a number of compressors to operate, and the operating frequency of each of the compressors in operation, and wherein the number control unit is further configured to determine, based on the required total operating frequency determined by the computation and the number control information, the number of the compressors to operate and the operating frequency of each of the compressors in operation. 4. The air-conditioning system of claim 3, wherein the number control unit is further configured to perform, in satisfying the capacity demand, a number control in which one of the compressors is operated in an operating frequency within the corresponding one of the plurality of predetermined frequency ranges, when the required total operating frequency is within the corresponding one of the plurality of predetermined frequency ranges,the number of compressors in operation is sequentially increased in such a way that the operating frequency of each of the compressors in operation is within the corresponding one of the plurality of predetermined frequency ranges, when the required total operating frequency is not within the sum of the plurality of predetermined frequency ranges, anda number of compressors that operate at a maximum operating frequency thereof is increased while sequentially decreasing a number of compressors that operate at operating frequencies that are within the plurality of predetermined frequency ranges when the capacity demand are not satisfied even when all the compressors are operated in the plurality of predetermined frequency ranges,based on the required total operating frequency determined by the computation and the number control information. 5. The air-conditioning system of claim 3, wherein the number control unit is further configured to generate the number control information based on connected model information regarding a capacity and performance of the outdoor units, and on a number of connected outdoor units. 6. The air-conditioning system of clam 1, wherein the plurality of outdoor units have the same capacity. 7. The air-conditioning system of claim 6, wherein the number control unit is further configured to select the compressors to operate so that the compressors are operated with priority in ascending order in length of operation time. 8. The air-conditioning system of claim 1, wherein the plurality of outdoor units include a combination of outdoor units, a part or all of which have different capacities. 9. The air-conditioning system of claim 8, wherein the number control unit is further configured to select the compressors to operate so that the compressors are operated with priority in ascending order in capacity of the outdoor units. 10. The air-conditioning system of clam 1, further comprising: an air handling unit controller including: an actuator control unit configured to control an actuator included in the air handling unit;a capacity calculation unit configured to generate the capacity demand corresponding to the air-conditioning load; anda communication unit configured to transmit the capacity demand to the number control unit; anda relay device including an interface configured to perform communication between the air handling unit controller and the plurality of outdoor units,wherein the number control unit is included in the relay device. 11. The air-conditioning system of claim 10, wherein the relay device is included in each of the plurality of outdoor units. 12. The air-conditioning system of claim 1, further comprising: an air handling unit controller including: an actuator control unit configured to control an actuator included in the air handling unit;a capacity calculation unit configured to generate the capacity demand corresponding to the air-conditioning load; anda communication unit configured to transmit the capacity demand to the number control unit;a relay device including an interface to perform communication between the air handling unit controller and the plurality of outdoor units; anda remote control connectable to the relay device,wherein the number control unit is included in the remote control. 13. The air-conditioning system of claim 1, further comprising an air handling unit controller including: an actuator control unit configured to control an actuator included in the air handling unit;a capacity calculation unit configured to generate the capacity demand corresponding to the air-conditioning load; anda communication unit configured to transmit the capacity demand to the number control unit,wherein the number control unit is included in the air handling unit controller. 14. The air-conditioning system of claim 1, wherein each of the plurality of independent heat pump cycles includes a four-way valve configured to switch a direction in which refrigerant flows, and the switching of the four-way valve enables switching between a heating operation and a defrosting operation,wherein each of the plurality of outdoor units includes: a frosting detection unit configured to detect a frosting state of the outdoor heat exchanger; anda communication unit configured to transmit, before start of the defrosting operation of the outdoor heat exchanger of the outdoor unit, a detection result of the frosting detection unit to the number control unit, andwherein the number control unit is further configured to control a timing to perform the defrosting operation of the each of the plurality of outdoor units based on the detection result from each of the plurality of outdoor units.