A study on refrigerant leak and frost detection for a refrigeration system

Professor Min Soo Kim, Seoul National University

In order to increase the efficiency and extend the life span of the heat pump system, it is important to detect and diagnose faults of the heat pump system. In this study, the theoretical analysis of refrigerant leakage and frost accumulation, two major faults of heat pump, is performed. Through the analysis, a method of predicting the refrigerant charge and detecting the defrosting time using the sensor signal were proposed. The prediction equation of the refrigerant charge amount is presented through the analysis of liquid refrigerant amount in the condenser. The prediction accuracy is high with 3.72% RMS error. By analyzing the variables affecting the frost accumulation rate, the detection method of the defrosting time is presented. It was possible to determine the proper timing of defrost mode entry using the sensor information.