| 摘要 |
PROBLEM TO BE SOLVED: To shorten the defrosting operation time and avoid the drop of heating comfortableness by providing this system with a hot water extraction part at the middle of a hot water reservoir, and performing the defrosting operation, making use of the heat of the hot water extracted out of this hot water extraction port. SOLUTION: This system is provided with a hot water extraction port 9 at the middle of a hot water reservoir 1, and also is provided with a passage switching means 27 which switches the first switching condition where the outflow of the water from the hot water reservoir 1 to a heat exchanger 5 is performed via a water outlet 7 and the second switching condition where the outflow of the hot water is performed via a hot water extraction port 9. Then, the passage switching means 27 puts it in the first switching condition when there is request for hot water supply, while it puts it in the second switching condition when there is a request for defrosting, whereby it lets the hot water flow out from the hot water extraction port 9 so as to circulate the hot water in the heat exchanger 5, and also it makes a water heat exchanger 4 function as an evaporator. Hereby, the defrosting time can be shortened, and also the drop of the heating comfortableness can be avoided. |
