| 摘要 |
PROBLEM TO BE SOLVED: To provide efficient operation as a screw compressor for a screw chiller. SOLUTION: The screw compressor is for the screw chiller, and it is provided with a pair of screw rotors, a housing housing the pair, a capacity control valve capable of varying a capacity ratio, a motor driving the screw rotors, and an inverter capable of varying a rotational frequency of the motor. In the screw compressor, control is carried out by singularly using or using both of a rotation frequency control means by the inverter in response to a load and a mechanical capacity control means by the capacity control valve, a maximum efficiency point is set to a lower rotational frequency side than a rated driving point when carrying out singular capacity control by the inverter, and control by only the inverter is carried out until a higher rotational frequency side than a rated rotational frequency in an area of a higher rotational frequency than the maximum efficiency point. COPYRIGHT: (C)2008,JPO&INPIT
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