| 摘要 |
PURPOSE:To permit the efficient obtaining of high-temperature hot-water, by a method wherein the first refrigerating cycle of a low boiling point refrigerant is employed when a water temperature is low in a hot-water supplying system consisting of a heat pump while a cascade system is employed when the water temperature has risen in some degree. CONSTITUTION:Water in a hot-water supplying tank 14 is sent by a pump 13 into the utilizing side heat exchangers 4, 6 of first and second refrigerating cycles I, II. When a water temperature in the hot-water supplying tank 14 is low, a three-way changeover valve 12 is switched to a pipeline 17 to the utilizing side heat exchanger 4 while another three-way changeover valve 7 is switched to another pipeline 10 to the utilizing side heat exchanger 4 whereby only the first refrigerating cycle I is operated. When the water temperature becomes higher than a predetermined temperature by this operation, the three-way changeover valve 12 is switched to the other pipeline 16 to the utilizing side heat exchanger 6 and the three-way changeover valve 7 is switched to the side of a pipeline 11 to a refrigerant-refrigerant heat exchanger 5 whereby the second refrigerating cycle II is operated in addition to the first refrigerating cycle I. Accordingly to this operation, hot-water in the tank 14 is heated by the heat exchanger 6 and hot-water, having the temperature of about 100 deg.C, may be obtained. |
