Fault detection for systems with multiple unknown modes and similar units - Part II: Application to HVAC

This paper deals with fault detection in Heating Ventilation and Air Conditioning (HVAC) systems. Reliable and timely fault detection is a significant (and still open) practical problem in the HVAC industry—commercial buildings waste an estimated 15% to 30% ($20.8B – $41.61B annually) of their energy due to degraded, improperly controlled, or poorly maintained equipment. The paper is a continuation of a companion paper [1] where a new approach and algorithm for fault detection in large-scale systems with multiple similar units operating in a shared environment have been developed in a general theoretical setting. This second part is focused on the application of the new methodology to practical HVAC systems. It addresses important details of the implementation of the general algorithm to this application, and presents results from an extensive performance study based on both Monte Carlo simulations as well as real data collected from three operational large HVAC systems. The results demonstrate the capabilities of the new methodology in a more realistic setting and provide insights that can facilitate the design and implementation of practical fault detection for systems of similar type in other industrial applications.