| 摘要 |
PROBLEM TO BE SOLVED: To improve the performance and efficiency of an air conditioner composed of a waste heat utilizing circuit utilizing the waste heat of a heat source in heating a conditioned room by a heat exchanger for heating, a refrigerant circuit using a carbon dioxide as a refrigerant and having supercritical pressure at a high pressure side, and a cascade heat exchanger exchanging heat between the fluid flowing from the heat source to the heat exchanger for heating in the waste heat utilizing circuit and the refrigerant of the refrigerant circuit. SOLUTION: An opening of an auxiliary expansion valve 15 for heating as an auxiliary pressure reducing device is controlled so that the temperature difference between a temperature of one of refrigerants coming out of the auxiliary heat exchanger 17 for heating as an internal heat exchanger and a temperature of one of refrigerants entering into the auxiliary heat exchanger 17 for heating is 20 K or lower, and a superheating degree of the refrigerant of an intermediate pressure portion of the compressor 11 is 2 K or higher. COPYRIGHT: (C)2007,JPO&INPIT
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