| 摘要 |
A refrigerant circuit ( 10 ) of a refrigeration apparatus is filled up with carbon dioxide as a refrigerant. In the refrigerant circuit ( 10 ), a first compressor ( 21 ) and a second compressor ( 22 ) are arranged in parallel. The first compressor ( 21 ) is connected to both an expander ( 23 ) and a first electric motor ( 31 ), and is driven by both of the expander ( 23 ) and the first electric motor ( 31 ). On the other hand, the second compressor ( 22 ) is connected only to a second electric motor ( 32 ), and is driven by the second electric motor ( 32 ). In addition, the refrigerant circuit ( 10 ) is provided with a bypass line ( 40 ) which bypasses the expander ( 23 ). The bypass line ( 40 ) is provided with a bypass valve ( 41 ). And, the capacity of the second compressor ( 22 ) and the valve opening of the bypass valve ( 41 ) are regulated so that the COP of the refrigeration apparatus is improved after enabling the refrigeration apparatus to operate properly in any operation conditions.
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