Measurement and statistical evaluation of hot water tapping profiles in (non-)residential buildings

Abstract

For a good design of water heaters, an exact knowledge of the hot water demand and its temporal distribution is required. According to DIN EN 12831-3, cumulative demand profiles must be determined that represent the daily tapping behavior in the building. In addition, knowledge of the simultaneity of tapping events and thus of the maximum tapping capacity is crucial for the use of central instantaneous water heaters (IWH), which offer advantages for the integration of regenerative heat generators. The following article presents the results of two measurement campaigns to record the domestic hot water demand in residential and non-residential buildings. In 19 water heaters of multi-family houses and 10 water heaters of non-residential buildings, data on temperature and volume of the domestic hot water and, if available, of the circulation are determined. The applied measurement technology for this purpose is presented. The recorded data is analyzed with the help of a Python tool. At first the focus is put on the necessary measuring period and the measuring interval. It is recommended to measure for at least four weeks and with a measurement interval of 5 s or less to be able to make reliable statements about load peaks for the design of IWH. Furthermore, cumulative demand profiles for multi-family houses and hotels are presented, showing that the profiles in the hotel depend on the change of guests checking in to checking out. In addition, the simultaneity of tapping events in non-residential buildings is considered and a good match with formulas for residential buildings from VDI 2072 is achieved.