Patent ID: 7640762

Claim:
A refrigeration apparatus comprising: a single screw compressor including a screw rotor and two gate rotors which mesh with the screw rotor so as to sandwich the screw rotor from both sides; a condenser operatively connected to the compressor; an expansion part operatively connected to the condenser; an evaporator operatively connected between the expansion part and the compressor, the compressor, the condenser, the expansion part and the evaporator being connected to one another in a loop; a plurality of sub passages branched from a main passage located between the condenser and the expansion part and connected to the compressor, a first one of the sub passages being connected to a compression chamber located on one side of a boundary defined by the gate rotors, and a second one of the sub passages being connected to a compression chamber located on another side of the boundary defined by the gate rotors; a plurality of supercooling-use expansion parts with a first of the supercooling-use expansion parts being provided on the first sub passage and a second of the supercooling-use expansion parts being provided on the second sub passage; a plurality of supercooling-use heat exchangers with each one of the supercooling-use heat exchangers performing heat exchange between refrigerant on an outlet side of one of the supercooling-use expansion parts and refrigerant of the main passage; a discharge-side supercooling control section configured to detect temperature and pressure of a refrigerant on a discharge side of the compressor and control an opening degree of the supercooling-use expansion part in the first one of the sub passages based on the detection; and a suction-side supercooling control section configured to detect temperature and pressure of a refrigerant on a suction side of the compressor in the second one of the sub passages and control an opening degree of the supercooling-use expansion part in the second one of the sub passages, the supercooling-use expansion parts on the first and second sub passages being controlled based on different temperatures and pressures, respectively; and the first sub passage branches from the main pipe to the first supercooling-use expansion part at a location downstream of where the second sub passage branches from the main pipe to the second supercooling-use expansion part.