3899 -- Fault Direction Space Method for On-Line Fault Detection PDF

A new procedure for on-line fault detection of heating, ventilating, and air conditioning (HVAC) components or subsystems is presented. Characteristic parameters (CP) are used to indicate the abnormal state so as to replace the on-line performance prediction models. A fault direction space (FDS) is then introduced to represent the knowledge of fault. The FDS is constructed by the variations of CPs. Different kinds of faults will be in different directions in the FDS. Therefore, the type of fault can be distinguished by comparing the measured direction of the CP with the standard fault directions. An "if-then" reasoning procedure can then be replaced by multiplying the FDS matrix with the CP vector. In this way, the threshold can be avoided in the diagnostic process. This procedure is introduced with a heat exchanger as an example. Validation is also provided with simulation and on-site measurements.

KEYWORDS: year 1995, failure, detectors, monitoring, building services, heating, ventilation, air conditioning, components, computers, building management, energy management, controls