| 摘要 |
PURPOSE:To reduce a pressure loss and save an electrical energy with a ventilating operation being performed except a cooling/heating operation time by a method wherein a heat exchanging ventilation passing through a heat exchanger in the ventilation fan and a normal ventilation not passing through the heat exchanger are changed over automatically in response to a difference in temperature between the in-door and out-door temperatures. CONSTITUTION:Resistance value of the in-door temperature sensor 28 is made to be lower than that of an out-door temperature sensor 29 when the in-door tempreature is higher than the out-door temperature under a heating condition, and the terminal voltages V1, V2 are made to show a relation of V1<V2. When the differenc in voltages is exceeded over a predetermined value, the output value of the comparator 30 becomes a value of H. In turn,when cooled, the relation between V1 and V2 shows V1>V2 and subsequently when the difference in voltages becomes more than a predetermined value, the output of the comparator 31 becomes a value of H. In this way, when the output of either one of the comparators 30, 31 becomes a value of H, the switchin unit 27 causes each of the motors 26 for suction and exhaust fans to be rotated at a high speed. And the solenoid 25 is energized by a driver circuit 49, the ventilation holes 11, 12 are released to open by a downward movement of the shutter 17 to cause a heat exchanging ventilation condition. |
