Using thermodynamic impact for detecting refrigerant leaks in vapor compression equipment

A technique for detecting refrigerant leaks by utilizing their impact on the thermodynamic states of the vapor compression cycle is described. Simulation and laboratory experiments were performed to determine which of 7 inexpensive measurements contribute significantly to detection confidence. Experimental results show that suction line superheat and liquid line subcooling are the minimum measurements needed to detect and isolate refrigerant leaks from the other faults considered and provides 99.9% detection confidence with 5.5% charge loss. The addition of a hot gas line temperature sensor improves performance by allowing a 4.3% loss of charge to be detected with the same confidence. Adding more measurements did not enable smaller leaks to be detected.