Hourly consumption profiles of domestic hot water for different occupant groups in dwellings

Hourly consumption data of domestic hot water (DHW) is essential to compute the energy demand, and for system sizing. Few on-site measured data and simulation based studies are available to forecast DHW consumption focusing on a daily average, hourly average, appliance consumption, and occupant number. This study derived the hourly DHW profiles for 5 different groups of 1 person, 3 people, 10 people, 31 people and more than 50 people as a function of the number of occupants. Weekday (WD), Weekend (WE) and Total day (TD) consumption variation were analyzed. The study accomplished with on-site hourly DHW consumption measurement from 86 apartments with 191 occupants during one year and findings was also validated against a larger sample from previous study. A specific selection procedure was developed to find out the most representative DHW profile among measured candidates of each group fulfilling the selection criteria. Selected profiles had similar daily consumption (L/per./day) to an average of all profiles and also followed similar consumption pattern during a day. Two sharp peaks with large consumption variance were found in each day and smaller groups had higher consumption during peak hours. Result also found higher evening peak compared to the morning peak and the average consumption of peak hours was 2-4 times higher than non-peaks hours. Morning peaks of WE shifted 2-3 h later from WD's and kept similar position during the evening. Profiles of 5 groups were necessary to normalize with scaling factor to maintain the daily average value. Derived hourly values could be used with monthly factors to deliver hourly profiles of all months and the format of hourly and monthly factors used allows to define DHW consumption in relevant simulation and sizing software.