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Systems and methods for energy cost optimization in a building system

United States Patent

September 6, 2016
View the Complete Patent at the US Patent & Trademark Office
Methods and systems to minimize energy cost in response to time-varying energy prices are presented for a variety of different pricing scenarios. A cascaded model predictive control system is disclosed comprising an inner controller and an outer controller. The inner controller controls power use using a derivative of a temperature setpoint and the outer controller controls temperature via a power setpoint or power deferral. An optimization procedure is used to minimize a cost function within a time horizon subject to temperature constraints, equality constraints, and demand charge constraints. Equality constraints are formulated using system model information and system state information whereas demand charge constraints are formulated using system state information and pricing information. A masking procedure is used to invalidate demand charge constraints for inactive pricing periods including peak, partial-peak, off-peak, critical-peak, and real-time.
Turney; Robert D. (Watertown, WI), Wenzel; Michael J. (Oak Creek, WI)
Johnson Controls Technology Company (Holland, MI)
13/ 802,279
March 13, 2013
GOVERNMENT LICENSE RIGHTS This invention was made with government support under contract number DE-EE0003982, awarded by the U.S. Department of Energy. The government has certain rights in the invention.