Characteristics of Domestic Hot Water Consumption Profiles in Multi-Family Buildings for Energy Modeling Purposes

This paper presents a domestic hot water (DHW) consumption model for multi-family residential buildings that captures demand variability across monthly, daily, and hourly timescales. The model enables both the disaggregation of annual consumption for dynamic simulations and the generation of synthetic yet realistic DHW load profiles when detailed measurements are unavailable. It is developed from a dataset of 42 buildings containing 1376 apartments. The analysis identifies seasonal, weekly, and hourly usage patterns, reflecting the influence of apartment layout, building size, and user behavior under Polish climatic and cultural conditions. The proposed model reproduces seasonal deviations of up to 23%, with average daily demand falling to 77% of the annual mean in August and rising above the yearly average during winter months. It also captures weekly variability, with weekend consumption exceeding weekday levels by more than 16%. On working days, the hourly profile exhibits a clear dual-peak structure, with approximately 18% of daily demand occurring in the morning and up to 45% in the evening, whereas weekends show a flatter distribution without pronounced peaks. These results provide a robust basis for more accurate demand representation in energy modeling, system design, and optimization under local conditions.