| 摘要 |
A refrigeration system includes a compressor, a condenser, an expansion device and an evaporator connected in a closed circuit through which a refrigerant is circulated. A portion of liquid refrigerant exiting the condenser is diverted through a secondary expansion valve and a heat exchanger, which is thermally coupled between compressor and condenser, thereby allowing the superheated refrigerant vapor to be cooled at a temperature at or close to its saturation temperature when it enters the condenser. Hence, a de-superheating process inside the condenser is eliminated, and the condenser operates more efficiently, resulting in increased subcooling and thus increased cooling capacity. Also, the more efficient condenser decreases condenser pressure, a phenomenon which results in the reduction of the compressor work and accordingly increases the efficiency. The refrigerant vapor from the bypass line is maintained at an intermediate pressure between evaporator and condenser pressures and is combined with the low-pressure vapor from the evaporator through a pressure differential accommodating device, which may generate a vacuum by vortex flow of the superheated vapor from the bypass line, by flow of the superheated vapor through the throat of a venturi device, or in any other comparable manner. By increasing the amount of diverted refrigerant beyond that required for de-superheating, reduced cooling capacity can be achieved without the need for frequent on-off cycling of the compressor. The refrigeration system may employ a single refrigerant or a mixture of refrigerants such as R-134a, R-32 and R-125.
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