Freezer apparatus

A refrigeration system, comprising:

• a main refrigeration circuit including a compressor, a heat-source-side heat exchanger, and a user-side heat exchanger;
• a discharge temperature detecting mechanism provided in the main refrigerant circuit and configured to detect a discharge temperature of the refrigerant at a discharge side of the compressor;
• a bypass refrigerant circuit connected to the main refrigerant circuit and configured such that a portion of the refrigerant flowing from the heat-source-side heat exchanger to the user-side heat exchanger is diverted from the main refrigerant circuit and returned to an intake side of the compressor;
• a bypass expansion mechanism provided in the bypass refrigerant circuit and configured to regulate a flow rate of the refrigerant flowing through the bypass refrigerant circuit;
• a cooling device configured and arranged to cool the refrigerant flowing from the heat-source-side heat exchanger to the user-side heat exchanger in the main refrigerant circuit using the refrigerant that exits the bypass expansion mechanism and flows to the intake side of the compressor;
• a superheating degree detecting mechanism is provided in the bypass refrigerant circuit and configured to detect a superheating degree of the refrigerant at an outlet side of the cooling device;
• and
• an expansion mechanism control device configured to control the bypass expansion mechanism based on the superheating degree detected by the superheating degree detecting mechanism such that the superheating degree of the refrigerant flowing through the bypass refrigerant circuit is substantially equal to a prescribed superheating degree,
• the value of the prescribed superheating degree being set based on the discharge temperature detected by the discharge temperature detecting mechanism such that wet compression does not occur in the compressor.