Load frequency control by aggregations of thermally stratified electric water heaters

In this paper, we present a dynamic model of an electric water heater which describes the thermal stratification inside the water tank. The goal of this modeling is to accurately describe the power consumption behavior of a large water heater population and to assess customer comfort loss (lack of hot water) in the presence of external control actions. We present four rule-based control approaches for aggregate power setpoint tracking and compare them by means of time-domain simulations and numerical comparisons. As a control signal, we use a scaled load frequency control (LFC) time series added to a time-varying baseline of the aggregate water heater load.

[1]  Duncan S. Callaway.  Tapping the energy storage potential in electric loads to deliver load following and regulation, with application to wind energy , 2009 .

[2]  M.H. Nehrir,et al.  Power Management of Aggregate Electric Water Heater Loads by Voltage Control , 2007, 2007 IEEE Power Engineering Society General Meeting.

[3]  A. Bejan,et al.  Thermal Energy Storage: Systems and Applications , 2002 .

[4]  A. H. Fanney,et al.  The Thermal Performance of Residential Electric Water Heaters Subjected to Various Off-Peak Schedules , 1996 .

[5]  Chong Hock K. Goh.  Consumer Strategies for Controlling Electric Water Heaters under Dynamic Pricing , .

[6]  Stephan Koch,et al.  Potentials and applications of coordinated groups of thermal household appliances for power system control purposes , 2009, 2009 IEEE PES/IAS Conference on Sustainable Alternative Energy (SAE).

[7]  David M. Auslander,et al.  Using load switches to control aggregated electricity demand for load following and regulation , 2011, 2011 IEEE Power and Energy Society General Meeting.

[8]  William M. Healy,et al.  Variability in Energy Factor Test Results for Residential Electric Water Heaters , 2003 .

[9]  R. Schreiber.  Numerical Methods for Partial Differential Equations , 1999 .

[10]  Zhao Xu,et al.  Demand as Frequency Controlled Reserve , 2011, IEEE Transactions on Power Systems.

[11]  Jim Lutz.  Water Heaters and Hot Water Distribution Systems , 2012 .

[12]  Liuchen Chang,et al.  A novel domestic electric water heater model for a multi-objective demand side management program , 2010 .

[13]  Johanna L. Mathieu,et al.  Modeling and Control of Aggregated Heterogeneous Thermostatically Controlled Loads for Ancillary Services , 2011 .

[14]  J. Varah.  Stability Restrictions on Second Order, Three Level Finite Difference Schemes for Parabolic Equations , 1978 .

[15]  Hosam K. Fathy,et al.  Modeling and control insights into demand-side energy management through setpoint control of thermostatic loads , 2011, Proceedings of the 2011 American Control Conference.

[16]  Johanna L. Mathieu,et al.  State Estimation and Control of Heterogeneous Thermostatically Controlled Loads for Load Following , 2012, 2012 45th Hawaii International Conference on System Sciences.

[17]  M. Pfeiffer.  Load Control Strategies for Electric Water Heaters with Thermal Stratification , 2011 .