| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a two-stage pressure buildup refrigeration cycle having a satisfactorily improved COP independent of a change in necessary circulating coolant flow rate required to be circulated in the cycle. <P>SOLUTION: An intermediate pressure side stop valve 14a is arranged in an intermediate pressure coolant passage 14 for guiding an intermediate pressure coolant to the suction sides of a low-stage side compression mechanism 110 and a high-stage side compression mechanism 120, a low pressure side stop valve 22a is arranged in a low pressure coolant passage 22 which connects the coolant passage for guiding a low pressure coolant to the suction side of the low-stage side compression mechanism 110 with the intermediate coolant passage 14. In accordance with deterioration in the heating capacity (necessary coolant circulation flow rate) necessary for the cycle, the following switching is performed: a first coolant circuit in which the intermediate pressure side stop valve 14a is opened and, at the same time, the low pressure side stop valve 22a is closed → a third coolant circuit in which the intermediate pressure side stop valve 14a is closed and, at the same time, the low pressure side stop valve 22a is closed → a second coolant circuit in which the intermediate pressure side stop valve 14a is closed and, at the same time, the low pressure side stop valve 22a is opened. <P>COPYRIGHT: (C)2012,JPO&INPIT |
