MODEL BASED FAULT DETECTION AND DIAGNOSIS METHODOLOGY FOR HVAC SUBSYSTEMS

摘要

A fault detection system for an HVAC system includes sensors for measuring performance of a condenser, compressor, evaporator and chiller. A thermodynamic preprocessor calculates characteristic quantities (CQ's) from measured inputs. A base-case lookup table stores a first set of CQ values generated by the preprocessor during a period of fault-free operation of the HVAC system, a first set of CQ values being generated for each of the measured input values. A set of base-case CQ values is interpolated from the first sets of CQ values stored in the lookup table for a given set of measured inputs. A fault is detected when a difference between actual CQ values and base-case CQ values exceeds a predetermined threshold value for at least one of the CQ values. A detected fault is classified based on which ones of the actual CQ values exceed the interpolated CQ values.