| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a fear that refrigerating machine oil is retained in piping so that the shortage of an amount of oil in a compressor is generated in a refrigerating and air-conditioning cycle device using the refrigerating machine oil incompatible or weakly compatible with a refrigerant. SOLUTION: The refrigerating and air-conditioning cycle device has a refrigerant circuit in which the compressor, an outdoor heat exchanger, a flow regulating valve, and a plurality of indoor heat exchangers are sequentially connected and uses the refrigerating machine oil incompatible or weakly compatible with the refrigerant. The rotating speed of the compressor or the opening degree of an expansion valve is controlled so that the flow velocity of the refrigerant in a riser tube which flows upward from the lower part of the piping is higher than the flow velocity at which oil adhering to the inner wall of the piping is raised.
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