Intelligent pressure management by pumps as turbines in water distribution systems: results of experimentation

Pressure reducing valves (PRVs) are used in water distribution networks (WDNs) for pressure control and water loss reduction. In this study, a system composed of a PRV and a pump as turbine (PAT) in combination with intelligent pressure management is proposed and its performance is analysed experimentally. For this, data analysis using hydraulic modelling and extensive experimentation for a case study in Germany was performed. During the laboratory tests, the pressure at the critical point of the system could be successfully maintained at the selected value at variable discharges during a characteristic day, as a result of the advanced pressure modulation. Additionally, up to 2.3 kW of electrical energy were recovered, when the applied PAT was operating under full load, with a maximum total net system efficiency of 40%. Furthermore, the proposed pressure management was found to increase the water savings by up to 16% compared to conventional PRVs. This study concludes that the PAT-PRV-system may be suitable in WDNs with high differences in altitude, high operational pressures and high demand variability. For its application, the benefits and the investment costs, as well as the seasonal flow and pressure variations in the WDN should be analysed in detail.