PURPOSE: To provide a refrigerating plant in which the liquid refrigerant accumulating in a liquid separator, after gasification, can be returned to the compressor without involving a liquid back where no heat source is provided outside.

CONSTITUTION: A closed refrigerant line 20 is provided, which includes an oil-cooled positive-displacement compressor 11, oil-separating reclaimer 1, first four-way directional control valve 13, air heat-exchanger 14, second four-way directional control valve 15, liquid receiver 16, expansion valve 17, second four- way directional control valve 15, water heat-exchanger 18, first four-way directional control valve 13, and liquid separator 2. Furthermore an oil-feeding line 24 is provided as a means of feeding oil cooled by an oil cooler 22 to lubricating points in the compressor 11, such as the rotor chamber, bearings, and shaft seal parts, and making the oil circulate. Moreover, the oil-separating reclaimer 1 and the liquid separator 2 adjoin with a partition 3 in between so that heat exchange can be effected between the oil O in the former and the liquid refrigerant C in the latter.