PURPOSE: To accomplish a refrigeration cycle with favorable efficiency, by providing a controlling means for processing signals from a temperature-detecting means and a time-integrating means and operating a defrosting means, whereby a defrosting operation is conducted when the quantity of frost is small, in a heating operation under an overload.
CONSTITUTION: The temperature detector 8 is provided in contact with a V-bend part of an exterior-side heat exchanger 2. A signal from the temperature detector 8 is fed to a controller 9 comprising a micro-computer, and in accordance with the signal, a four-way valve 5 and an exterior-side blower 6 are controlled, thereby conducting a defrosting action. In a heating operation, the operating periods are integrated by the controller 9, and the defrosting action is effected only when the integrated operating period exceeds a predetermined period of time and the temperature detected by the detector 8 is lower than a predetermined value.
SHIMOKAWA NAOKI
MOGI HITOSHI
