| 摘要 |
<P>PROBLEM TO BE SOLVED: To enhance COP by making an internal pressure of an expander casing appropriate. <P>SOLUTION: An expander (30) is provided with an expansion mechanism (31) for expanding a refrigerant having flowed in directly from the outside of an expander casing (34) and for causing the refrigerant to directly flow out to the outside of the expander casing (34). The same includes a refueling piping (41) through which a refrigerating machine oil contained in a compressor casing (24) is supplied to the expansion mechanism (31), an oil return piping (42) for returning a refrigerating machine oil leaked from the expansion mechanism (31) and accumulated in the expander casing (34) to the suction side of a compressor (20), and a throttle valve (43) provided on the oil return piping (42). An opening degree of the throttle valve (43) is adjusted so that actual temperature inside the expander casing (34) may become higher than a saturation temperature which is equivalent to the internal pressure of the expander casing (34). <P>COPYRIGHT: (C)2012,JPO&INPIT |
