Load flexibility quantification of electric water heaters under various demand-side management strategies and seasons

The load flexibility of domestic water heaters was explored considering various demand-side management (DSM) strategies and seasons in this study. Physics-data driven models for electric resistance water heaters (EWHs) were developed. A data-driven approach was proposed to identify the model parameters of EWH models, enabling the inference of model parameters without knowledge of the detailed specific physical parameters of EWHs. This method provides substantial convenience for the application of the developed models in practical engineering. The model validation results indicate the accuracy of the developed EWH model, with a relative root mean square error of 1.9 %. Based on the validated model, the load flexibility potential of EWHs was quantified under seven DSM strategies and on five typical seasonal days, utilizing four evaluation indicators. Additionally, an integrated quantification index was proposed to compare the load flexibility of EWHs under various strategies and seasons. Results show that EWH's load flexibility is the greatest on a typical summer day, with the integrated quantification index being 50.3 %, while it is 37.2 %, 35.0 %, 30.1 %, and 20.5 % on the other four typical seasonal days. Recommendations for the application of the seven DSM strategies in different seasons were provided, offering guidance for the demand-side management of EWHs in real-world settings. Two suggestions for the improvement of EWH products were offered to enhance the load flexibility of EWHs based on the sensitivity analysis results, providing guidance to EWH manufacturers for the further development of EWH products.