| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a supercritical vapor compression type refrigerating cycle provided with a high pressure shell type two-stage compressor reduced in suction heating loss and having high efficiency, and operated in a supercritical zone on a heat radiation side of carbon dioxide refrigerant. Ž<P>SOLUTION: This supercritical vapor compression type refrigerating cycle has: the two-stage compressor having an intermediate connecting circuit, and compressing the refrigerant in two stages; a first expansion device for reducing a pressure of the refrigerant to an intermediate pressure; a gas-liquid separator for separating the refrigerant into gas and liquid; an injection circuit for injecting the gas phase side refrigerant after the gas-liquid separation into the intermediate connecting circuit; and a second expansion device. A pre-expansion temperature is controlled so that an excluded-volume ratio of excluded volume on a high stage side to an excluded volume on a low stage side of the excluded volume ratio, is root of isentropic exponent of a ratio of a suction pressure of the two-stage compressor to a refrigerant saturated liquid pressure in the first expansion device or more, and an opening of the first expansion device is also controlled so as to make a pressure of the refrigerant injected into the intermediate connecting circuit, approach a square root of a product of a suction pressure and a discharge pressure. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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