| 摘要 |
PURPOSE:To reduce the running cost in a hot water supplying apparatus using a heat pump and an electric heater together by preferentially operating a heat pump having an excellent heat exchange efficiency in a time zone when electrical charges are moderate. CONSTITUTION:Power is supplied from a power supply 3 to a heater part which is comprises of a heat pump 1 and electric heaters H1, H2. The electric heater H1 can be switched on at all times while the electric heater H2 can be switched on in response to the current capacity thereof. A control part 6 composed of a microcomputer preferentially operates the heat pump 1 in a midnight time interval. More specifically, in the night time interval, hot water is heated by the heat pump 1 from the temperature thereof when supplied to the maximum boiling temperature of the heat pump 1 (about 65 deg.C) Thereafter, the hot water is heated to maximum boiling temperature 85 by the electric heater H1. |
