Automatic Commissioning of Multiple VAV Terminals

Abstract

A site survey on a modern operating commercial building screened 261 ineffective VAV (Variable Air Volume) boxes (20.9% of the total boxes in the building) and summarized ten typical faults for VAV air-conditioning system(s) resulting in energy waste, performance degradation or totally out of control. A strategy is developed to automatically check the health condition of VAV terminals and diagnose the faults. Hybrid approach is employed to establish a commissioning and re-commissioning tool of VAV air-conditioning system. Performance indices with expert rules based on system physical characteristics are adopted to detect and diagnose the nine of the ten faults. PCA (Principal Component Analysis) method is developed to detect and diagnose the VAV box flow sensor bias (Fault 10) and to reconstruct the faulty sensors. A multiple VAV fault FDD strategy for a VAV entire system is developed, which is validated in simulation and filed tests.