| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot water storage and hot water supply system capable of circulating high-temperature hot water heated by an auxiliary heat source device and guided by a heat utilizing circulation circuit to a heating circulation circuit without destroying thermal stratification in a hot water storage tank as freezing preventive operation in the heating circulation circuit.SOLUTION: An upstream end portion of a heating circulation circuit 9 extending from a lower part of a hot water storage tank 3 and a downstream end portion of a heat utilizing circulation circuit 8 returned to the lower part of the hot water storage tank 3 are configured by a common lower pipe part 12 extending from the lower part of the hot water storage tank and can be communicated/branched each other on a junction 13. In circulation operation of the heating circulation circuit 9 during freezing preventive operation, a discharge flow rate of circulation pumps 93 and 62 and a passage flow rate of a three-way selector valve 61 are changed and set so that a circulation flow rate of circulating hot water returned to the upper part of the hot water storage tank 3 becomes an extraction flow rate or more extracted from the upper part of the hot water storage tank 3 to the heat utilizing circulation circuit 8. |
