JP2510697B

PURPOSE:To prevent an excessive drop in compression pressure and at the same time attempt to maintain a low level of noises throughout the year by controlling the number of revolution of a blower used for a condenser by taking as control factors the temperature of condensation, level of noises which varies according to the number of revolution of the blower, and energy efficiency which varies according to the pressure of condensation. CONSTITUTION:Temperature of condensation is detected by a condensation temperature sensor 8 to control the number of revolution of a blower 7. When the condensation temperature is high, the blower is operated at 100% of the number of revolution to prevent an abnormal rise in the condensation pressure, and when the condensation temperature is low, the number of revolution is reduced to prevent an abnormal reduction in the condensation pressure. At a condensation temperature which lies between those two cases, the number of revolution of the blower at which the level of noises is as low as possible and the reduction in the energy efficiency is small is selected to set up the number of revolution of the blower for condensation temperature. By making, at this time, the variation in the number of revolution small it is possible to make small variable sounds other than absolute noise level values. And, for the period of about 30 seconds to one minute in the beginning of operation the operation of the blower at a higher number of revolution than for ordinary condensation temperature suppresses the dissolving of the coolant into the oil of a refrigerating machine.