| 摘要 |
PURPOSE:To constantly secure the heating capacity of not lower than the minimum heating capacity, by controlling the capacity of a circulating pump to maintain the heating capacity of a heat-pump heating unit to be constant when the enthalpy of a heat source is not larger than a predetermined value. CONSTITUTION:When the enthalpy ha of a heat source detected by a sensor 19 for the enthalpy is at a high level, a control logic change-over circuit 20 selects a temperature-basis controlling circuit 21, and when the enthalpy ha is at a low level, the circuit 20 selects a capacity-basis controlling circuit 22. In the controlling circuit 21, the rotating speed N of a pump 9 is determined by a controlling circuit 23 for the rotating speed N so that the output hot water temperature TH of the heat-pump heating unit 1 becomes equal to a temperature set point signal THS, and the amount Q of circulated water is determined. In the controlling circuit 22, a capacity-calculating circuit 24 calculates operating capacity KH on the basis of the output hot water temperature TH, water temperature TW and a detection signal (g) fed from a detector for the amount Q of circulated water, and a controlling circuit 23' for the rotating speed N of the pump 9 is so controlled that the operating capacity KH becomes equal to a capacity set point signal KS. |
