AT-01-14-1 -- Model-Based Fault Detection and Diagnosis for Cooling Towers PDF

A model-based method for the detection and diagnosis of faults in the cooling tower circuit of a central chilled water facility is presented. Faults that occur in the cooling water temperature sensor, the cooling tower pump, and the cooling tower fan are considered. The faults are detected through deviations in the values of characteristic quantities from the corresponding values for fault-free operation. The characteristic quantities chosen to represent the performance are the conductance-area product of the tower, the approach, the effectiveness, and fan power. With faults present, the deviations are significant, which allows the faults to be detected. The pattern of the deviations is different for each fault, allowing rules to be developed that allow diagnosis of the source of the fault.

Units: SI