| 摘要 |
PROBLEM TO BE SOLVED: To secure a required operation frequency without applying an excessive load to a compressor even when a rotational speed of a fan is changed. SOLUTION: A refrigerant is circulated from a heat-absorbing in-room heat exchanger 14 to a heat-radiating in-room heat exchanger 15 by driving a compressor 16, passing through or not passing through an out-door heat exchanger 18 by switching a four-way valve 17. The compressor 16 is driven at an operation frequency provided by adding a proportional value of a difference hereinafter to an integrated increase and decrease value, based on the difference between a target blast temperature and an actual blast-air temperature of the heat exchanger 15, at the time of heating. Since an upper limit of the operation frequency is not fixed even when a rotational speed of a fan 12 is switched and since the operation frequency is determined based on the difference between the target blast temperature and the actual blast-air temperature, excessive pressure is not generated ranging from the heat exchanger 15 to the compressor 16.
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