| 摘要 |
This heat pump unit (200) is provided with the following: a circulation path (210) in which a heat medium circulates; a compressor (230) that has an accommodation space (R) for accommodating a lubrication oil supplied to a compressor mechanism (232, 234), and that insulates and compresses the heat medium so as to elevate the temperature thereof; a condenser (240) that condenses the heat medium; an expansion valve (260) that reduces the pressure of and expands the heat medium; an evaporator (220) that vaporizes the heat medium; and a control unit (280) that controls the driving of the compressor and the degree of opening of the expansion valve. The control unit is configured so that, upon receiving an instruction for stopping the compression operation of the compressor, the control unit makes the degree of opening of the expansion valve smaller so as to maintain the height of the liquid surface of the lubrication oil accommodated in the accommodation space at at least a threshold value determined in advance, and stops the operation of the compressor after the expansion valve has completely closed. |
