Hot water supply system with storing tank

摘要

A hot-water supply system comprises a hot-water generating unit (1a) of heat-pump cycle driven by an electric motor and a hot-water storing tank (7), wherein the hot-water generating unit (1a) is generally operated during night hours because the electricity rate is lower than that during the day time. The system also has a solar battery unit (16) and the hot-water generating unit is operated by the electric power from this solar battery unit (16) when the electric power of this solar battery unit (16) is higher than a predetermined value, so that hot water is frequently generated by the hot-water generating unit (1a) by using the electric power from the solar battery unit (16). Accordingly, it is avoidable that the hot-water generating unit (1a) is operated by the electric power of normal electricity rate during the day time, which is higher than that for the night hours.