| 摘要 |
<P>PROBLEM TO BE SOLVED: To make a secondary refrigerant circuit effectively function in a heating operation and to improve the entire energy efficiency. <P>SOLUTION: A first expansion valve 23, a third heat exchanger 24 and a second expansion valve 25 are successively incorporated in a refrigerant pathway 17 between a first heat exchanger 18 and a second heat exchanger 19 in a primary refrigerant circuit 12. A second refrigerant of the secondary refrigerant circuit 13 absorbs heat from a first refrigerant by the third heat exchanger 24 in the heating operation. In the heating operation, heat energy is transferred to the first refrigerant from the second refrigerant by a fifth heat exchanger 44. Thus, an evaporation temperature of the first refrigerant is increased, and furthermore, an evaporation pressure of the first refrigerant is increased. A suction pressure of a first compressor 14 is increased by the increase of the evaporation pressure. As a result, the power of a first compressor 14 is reduced. <P>COPYRIGHT: (C)2013,JPO&INPIT |
