| 摘要 |
PROBLEM TO BE SOLVED: To effectively prevent a wet vapor suction to a compressor and to improve the life of the compressor by detecting the degree of superheat of refrigerant in a heat exchanger, and controlling to raise an operating frequency of the compressor by a predetermined value at the time when the degree of superheat is smaller than a target value by a predetermined value or more and the travel of a motor driven expansion valve is minimum. SOLUTION: In a cooling operation, an indoor temperature, a set indoor temperature, an indoor heat exchanger temperature and a suction side tube temperature are read. An operating frequency of a compressor 1 is controlled in response to a difference between the indoor temperature and the set indoor temperature, and a target value of the degree of superheat is set. The degree of superheat of refrigerant in the exchanger 5 is calculated from a difference between the suction side tube temperature and the exchanger temperature. A necessary amount of a valve opening operating to an opening of a motor driven expansion valve 4 at present time point in response to a difference between the set target value and the degree of superheat is obtained, and the valve 4 is operated to travel. In this case, when the degree is smaller by a predetermined value or more than the target value and the opening of the valve 4 is minimum, the operating frequency of the compressor is controlled to be raised by a predetermined value. |
