Numerical Model of a District Water Distribution System in Bucharest

“Teiul Doamnei” Pumping Station in Bucharest supplies the WDN of a district with about 40,000 inhabitants. The pumping station was refurbished in 2004, and variable speed pumps were installed. Due to this refurbishment and other improvements of the water networks, performed by the Water Company of Bucharest, the total energy consumption for 2012 dropped to about 25% with respect to the value recorded for 2004. The numerical model of the pumping station and it's attached water network with 250 pipes and 212 nodes was created in EPANET. Variable speed driven pumps functioning algorithm was implemented in EPANET via ruled-based control statements. The overall variation of pumps’ speed allowed by the controls is between 70% and 100%. For each of the 12 months in 2012, from the water consumption recorded at the pumping station, a mean daily value of the flow rate was derived. The daily variation of the hourly flow rate has been considered according to Romanian standard for drinking water supply quantities in urban sites of about 40,000 inhabitants. This variation was introduced in EPANET as flow pattern over a 24 h period. The mean daily value of the flow rate for each month, divided by the number of consumption nodes of the network, was added as base demand at each consumption node. The simulations were performed for a 24 h period, for each month, with a time step of 5 minutes (although flow rate variation is hourly, due to the limitations of EPANET, the hydraulic time step must be smaller than the flow rate pattern step). Monthly energy consumption computed values are in good agreement with the corresponding values recorded at the pumping station. The model we created can prove useful in performing other analysis in order to assess the functioning of variable speed driven pumps in a WDN.