The real-time model which is widely used in the detection of long pipeline leakage is applied to detect ammonia leakage in the pipeline of refrigeration systems in cold stores. The pipeline of refrigeration system with R22 is used to simulate the ammonia system. The real-time model of leak detection and positioning is set up through the dynamic characteristics of refrigerant and testing results of leakage. The model is verified by experiments and the result shows that the accuracy of leak detection can reach 3.0%

and the positioning precision and stability is related to the position of leakage

which indicates that it can efficiently and rapidly achieve leak detection and determine position of leakage. This research provides effective methods and theoretical basis for the safe operation of refrigeration system in cold stores.