Air-conditioning system having recirculating and flow-control means

Abstract

In a refrigerant system having a liquid trapping suction accumulator between the evaporator exit and the compressor entrance and a very short bore capillary as an expansion tube to replace the thermostatic expansion valve, a recirculating ejector is added to recirculate any liquid that may be trapped by the accumulator back into the evaporator inlet where it can be used to provide desired refrigerating effect without requiring additional work in the compressor. The expansion tube is positioned so that it functions as the primary nozzle of the ejector. Thus the high-pressure liquid refrigerant being expanded through the expansion tube becomes the prime mover that is needed to drive the liquid from the accumulator into the evaporator. Because the high-pressure liquid refrigerant must be expanded to the relatively lower evaporator pressure in any vapor cycle refrigeration system, the recirculating function is accomplished without using additional energy or penalizing system capacity. Additionally, a heat exchanger is provided to heat the liquid/vapor/oil mixture leaving the accumulator and to cool the high-pressure liquid feeding the ejector primary nozzle, thus thermodynamically compensating for the small amount of compressor work associated with liquid in the suction vapor by sub-cooling the high-pressure liquid en route to the evaporator.