| 摘要 |
PROBLEM TO BE SOLVED: To surely return oil to a compressor when a refrigerator oil floats on a liquid refrigerant inside an accumulator and to prevent the liquid refrigerant from returning to the compressor. SOLUTION: A heat pump device 100 includes oil returning circuits 21, 22, and 23 which are connected to the accumulator 5 at different height positions and have flow regulating valves V1, V2 and V3 midway. When density of the liquid refrigerant in the accumulator 5 is higher than that of the refrigerator oil, the flow regulating valve V1 is closed. The flow regulating valve V2 is opened temporarily and a temperature difference of a fluid, which flows through the oil returning circuit 22, on the inlet side and that on the outlet side of an internal heat exchanger 6 is measured, and according to the measured temperature difference, opening/closing of the flow regulating valves V2 and V3 is controlled. COPYRIGHT: (C)2011,JPO&INPIT |
