Selection of pumping configuration for closed water distribution systems

This paper provides an insight into the selection of the most suitable configuration for closed distribution systems (i.e., systems with no storage capacity). The analysis is developed considering a wide ranges of operational scenarios in terms of flows and required heads. For each scenario, various design configurations are considered and compared. Results show that using more than a minimum of pumps can have lower operational and total costs thanks to the pumps operating closer to their best efficiency point. Small additional benefits in terms of operational and total costs may be obtained as a result of the introduction of the variable speed drive in at least one of the station pumps. Similar costs are obtained in the configuration where large pumps are flanked by a small jockey pump operating at low demand times. The design solution made up of large pumps fitted with a downstream hydropneumatic tank also represents a valid alternative option from the economical viewpoint for small flows.