A model for the determination of residential water demand by the use of tracers

A model that determines nodal demands by making tracer concentration measurements at specific nodes is developed. The model minimizes the difference between calculated and measured tracer concentrations to determine the unknown demands. Even-, over-, and under-determined cases are considered. For the purpose of verifying the model, tracer concentrations obtained by the model for known demands are considered as measurements. Results showed that the model made very accurate prediction of the unknown demands for both the even-, and the over-determined cases. The under-determined case made less accurate but still good estimates of the unknown demands for the scenarios considered here. The relationship between the sensitivity of the measurement location to the unknown demand and the accuracy of the determined demand is verified. Results showed that the model makes accurate estimation of the unknown demands if measurements are made at sensitive nodes while errors are introduced to the determined demand as a result of assuming measurements at nodes of low sensitivity.