Development of a Dynamic Grey-box a Condensing Boiler Emulator

Abstract: HVAC systems significantly impact building energy use and operational faults can significantly reduce their efficiency. While data-driven fault detection and diagnosis techniques have become well-established, the ability to emulate faults is critical, given the lack of available fault data for algorithm training. This study develops a condensing heat exchanger emulator using thermodynamics and fault simulation. A hybrid gray-box approach with Bayesian optimization estimates heat transfer coefficients under varying conditions. Testing shows the model accurately matches nominal data and reliably simulates faults like fouling, scaling, and excess air. This tool enhances fault analysis, improving HVAC optimization and reliability.