Refrigerating system

摘要

A refrigeration system includes a variable-capacity compressor having a compression chamber for sucking and compressing a refrigerant and a crankcase surrounding a swash plate forming a drive portion for suction and compression, and a passage through which the refrigerant discharged from the outlet of the compression chamber passes at least through a condenser, an expansion means and an evaporator and is sucked into the inlet of the compression chamber of the compressor, the capacity of the compressor being changed by slanting the swash plate during its rotation. A pressure control device is provided in a refrigerant passage between the evaporator and the suction valve of the compressor whereby the pressure upstream thereof is controlled in such a manner that it does not decrease below a predetermined value, thereby preventing frosting of evaporator fins. A point partway along the passage upstream from the pressure control device and the crankcase of the variable-capacity compressor are communicated so that the capacity of the compressor may be controlled without controlling the pressure in the crankcase.