Dynamic modeling and simulation of a water supply system with applications for improving energy efficiency

This paper presents the dynamic simulation of an urban water supply system based on a phenomenological model of distributed parameters capable of predicting the hydraulic behavior and the energy consumption. This case study involves a segment of the supply and distribution water system in the city of Salvador (Brazil), and the analysis focuses on the pumping station, water mainline, and distribution tanks. The current operation of the system is performed through heuristic rules based on expert knowledge, and the control of discharge flow pumps is essentially on/off. The comparison between simulation results and measured data shows that the model describes the hydraulic network satisfactorily as it is able to predict the transient behavior of the flow along the water main line. Considering the high capacity and dimensions together with the intrinsic dynamic features (disturbances caused by the maneuvers in the pump operation and variable demand throughout the day), the use of dynamic modeling for the case studied is really needed for the simulation results to be consistent. Furthermore, the dynamic model and strategy used enables a careful analysis of the water supply system and represents a potential tool for the evaluation of control strategies and energy efficiency. The results show the potential gain in energy efficiency with the inclusion of frequency converters in the pumping system without considerable changes in the level of reservoirs and ensuring the total service demand.