PNNL

We develop a simulation-based approach to fault impact analysis for a single duct VAV system, and analyze the dynamic and steady-state impact of equipment physical faults on building operation. The simulation model, a virtual testbed, can capture physical faults in the HVAC system of a large commercial building. The model can be utilized for generating data that can then be analyzed to quantify the impact of single or multiple faults. We illustrate the implementation of three physical faults: supply air temperature sensor bias, outdoor air temperature sensor bias, and cooling coil valve stuck. We simulate each fault with several fault intensity levels and at different seasonal operating conditions. Then, we analyze the impact of the above-mentioned faults using the metrics. The results show that the impact of a given physical fault depends on implemented control logic sequence and the seasonal operating conditions.