| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve COP by making an internal pressure of an expander casing appropriate. Ž<P>SOLUTION: An expander (30) includes an expanding mechanism (31) for expanding a refrigerant directly flowing therein from the external of the expander casing (34) and allowing the refrigerant to directly flow out to the external of the expander casing (34), an oil supply pipe (41) for supplying a refrigerating machine oil in a compressor casing (24) to the expanding mechanism (31), an oil return pipe (42) for returning the refrigerating machine oil leaking out from the expanding mechanism (31) and accumulated in the expander casing (34) to a suction side of a compressor (20), and a throttle valve (43) disposed in the oil return pipe (42). An opening of the throttle valve (43) is adjusted so that an actual temperature in the expander casing (34) becomes higher than a saturated temperature corresponding to the internal pressure of the expander casing (34). Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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