A Modeling Approach to Characterize the Demand Flexibility of the Air Distribution System in Commercial Buildings
grid-interactive buildings, demand flexibility, HVAC, modeling
Commercial VAV systems have been a studied as potential flexible power consumption resources to provide these services. A significant limitation is the development of control oriented models for these systems that accurately control power consumption across timescales. To this end, we develop a modeling approach that characterizes the demand flexibility of the air distribution system in commercial buildings. The model maps all feasible terminal zone damper configurations to power consumption by identifying a system resistance model connected to a pressure-flow model of the supply fan. Under this model structure, the operational range of an installed system can be quantitatively bounded by the extreme resistance curves the air distribution system encounters. We also propose a simplified control algorithm that leverages this model structure to emulate a demand flexibility event. We validate this approach by calibrating a model in an experimental testbed and additionally testing the results in a simulation environment. A brief discussion of important properties and observations that can be derived from this approach as well as avenues for improvements is presented.