Control Strategy for Domestic Water Heaters during Peak Periods and its Impact on the Demand for Electricity

Because they store hot water, water heaters are easily-shifted loads that can be controlled to reduce peak demands. However, load shifting may have some detrimental consequences on the domestic hot water supply temperature if the heating element is deactivated for a long period of time. Furthermore, a new peak may be caused if a significant number of heaters are reactivated at the same time. This study presents a control strategy for water heaters that minimizes the pick-up demand when the heating elements are reactivated at the end of a load shifting period and that ensures, in all cases, the client's hot water supply. The study is based on a simulation model of a water heater that was experimentally validated and takes into account the diversity of the population's hot water withdrawal profile. More specifically, the data of 8,167 real water withdrawal profiles of several clients were input into the simulation model in order to evaluate the performance of water heaters under different operating conditions. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of University of Electronic Science and Technology of China (UESTC).