Simulating Nonresidential Water Demand with a Stochastic End-Use Model

Abstract

The end-use model SIMDEUM for residential water demand has been extended to incorporate nonresidential water demand. The model was developed to predict water-demand patterns with a small timescale (1 s) and small spatial scale (at the water meter connection). The end-use model is based on statistical information about users and end uses: data on occupancy; the frequency of use; duration and flow per water-use event; and the occurrence over the day of different end uses, such as flushing the toilet, doing the laundry, and washing hands. The model follows a modular approach, in that each type of building is composed of functional rooms, such as lodgings, restaurants, and conference rooms. A functional room is characterized by its typical users and water-using appliances. With this approach, nonresidential buildings’ water-demand patterns over the day can be simulated. The simulation results for an office building, a hotel, and a nursing home were compared to measured water-demand patterns with regard to attributes such as peak flow and daily total water use, as well as the shape of the pattern. The simulation results show a good correspondence to measured water demands. The end-use model is based on independent statistical information and not on flow measurements. The input parameters are available before any information on annual or daily water use is available; the parameters are not fitted on flow measurements. Therefore, the model is transferable to a diverse range of nonresidential water-demand types. The model can be applied in the design stage (prebuild), in scenario studies, and in distribution network models.