| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hot water heat source machine of high efficiency by ensuring necessary heating capacity without increasing a capacity of a low order-side refrigerating cycle. <P>SOLUTION: When an operational frequency of a low order-side compressor 11 becomes lower than a threshold value A, the opening of a low order-side expansion valve 15 is controlled so that a condensation temperature of a low order-side refrigerant in a low order-side condenser 14 becomes equal to a condensation temperature set value determined on the basis of the total efficiency, and when the operational frequency of the low order-side compressor 11 becomes higher than the threshold value A, the opening of the low order-side expansion valve 15 is controlled so that the condensation temperature of the low order-side refrigerant is increased according to the increase of the operational frequency of the low order-side compressor 11. <P>COPYRIGHT: (C)2012,JPO&INPIT |
