AT-96-03-4 -- A Generic Approach to Identifying Faults in HVAC Plants PDF

Describes a semi-qualitative model-based method of fault diagnosis that is suitable for generic applications over a range of different sizes and designs of heating, ventilating, and air conditioning (HVAC) plant items, such as terminal boxes and heating coils. The method requires no training data from the actual plant and is suitable for real-time implementation in packaged digital controllers or in the outstations of energy management and control systems. The scheme uses reference models describing fault-free and faulty operation that are generated from data produced by simulating a number of plants of the same type as the plant under test. The method of diagnosis takes account of the ambiguity introduced by using such generic reference models that can arise if the symptoms of correct and faulty operation, or of different faults, are similar at certain operating points. The results presented demonstrate that the scheme can successfully detect and identify faults in the cooling coil subsystem of an air-handling unit.

KEYWORDS: year 1996, failure, detectors, identifying, air handling units, heating, ventilation, air conditioning, building services, cooler batteries