Improving water and energy metabolism efficiency in urban water supply system through pressure stabilization by optimal operation on water tanks

Water supply consumes 2-3% of the worldwide energy. Water distribution system, which accounts for 70% electricity consumption of water supply, is a key link of urban water and energy metabolism. The operation of the secondary water supply system (SWSS) has great influence on the pressure stability and associated energy consumption as well as water loss of urban water distribution. This research developed an approach based on the hydraulic solver EPANET and genetic algorithm (GA) to investigate the impacts of two different operation strategies, user demand regulation (UDR) and tank level regulation (TLR) of SWSS, on pressure stability and energy efficiency. The results showed that the strategy of TLR could reduce the pressure fluctuations and increase the minimal pressure of the distribution network under the same supply-demand condition. Reduction of the pressure fluctuations is beneficial to the reliability and leakage control of pipe networks. Increase of the minimal pressure indicates that less energy is lost during the distribution. Therefore, the TLR strategy of SWSS can support to initiatively lower the water pressure of the pumps at the water plant outlet, thus improves the water and energy metabolism efficiency in urban water supply system.