Model Predictive Control for Mid-Size Commercial Building HVAC: Implementation, Results and Energy Savings

The paper presents field demonstration results from the implementation of a model predictive control formulation to optimize the operation of a variable volume, dual-duct, multi-zone HVAC unit serving an existing mid-size commercial building. This full-scale study is used to estimate the benefits of advanced building control technologies that can be integrated during a retrofit. The predictive control approach uses dynamic estimates and predictions of zone loads and temperatures, outdoor weather conditions, and HVAC system models to minimize energy consumption while meeting equipment and thermal comfort constraints. The paper describes the on-line hierarchical control system, including communication of the optimal control scheme with the building automation system, the controlled set points and the componentlevel feedback loops, as well as the performance benefits from the demonstration. The experiments conducted and the receding control algorithm implementation results are described. Site measurements show this algorithm, when implemented in state-of-the-art direct digital control systems, consistently yields energy savings of 60% or more relative to pre-configured rule-based schedules, without sacrificing indoor comfort conditions.