| 摘要 |
<p>PURPOSE:To enable reduction of a heating operation expense according to a change on a total consumption quantity of heat per a day, by a method wherein a state quantity corresponding to a change in the outside air temperature, and based on the detecting state quantity, a set temperature is varied in a high and low temperature direction reverse to that of a change in the outside air temperature. CONSTITUTION:When a hot water temperature set change-over switch 48 is on the automatic operation side, a set temperature Ds for hot water in a hot water storage tank 28 is automatically varied based on a feed water temperature changed according to a change in an outside air temperature. Varied high and low temperatures is directed to a maximum temperature (Ds=65 deg.C), to which a feed water can be heated by a heat pump system, when an outside air temperature is low, for example, during a winter season, and a feed water temperature is as low as approximate 10 deg.C, and the set temperature Ds is varied lower than the above when the outside air temperature is increased and a feed water temperature is also increased. As a result, since, also when the outside air temperature is increased, a set temperature is decreased, an amount of hot water used per a day is kept from a wide decrease. Thereby, a hot water surplus amount is decreased, and an effective hot water feed cycle can be maintained.</p> |
