TRANSIENT PERFORMANCE AND ENERGY RECOVERY POTENTIAL OF A PUMP AS TURBINE (PAT) IN WATER DISTRIBUTION NETWORKS: A COMBINED NUMERICAL AND EXPERIMENTAL STUDY

The present research is dealing with energy inefficiency in the Water Distribution Networks (WDNs) where the conventional method of dissipating excess pressure is by using Pressure Reducing Valves (PRVs). Sustainable alternative, which applies Pumps as turbines (PATs) to control pressure and recover energy simultaneously is explored. Nevertheless, the interaction of PATs in transient conditions, water hammer, is poorly known and this presents a knowledge gap. The literature is mostly restricted to steady-state performance, and a validated high-fidelity model that can be used to predict the transient PATs behavior does not exist. The main value of the work is the creation and experimental confirmation of a general numerical model to examine PATs transient operation and measure the energy recovery. It has a mixed numerical and experimental approach that entails experimental analysis within a laboratory-sized hydraulic loop to obtain the short-term occurrences and the creation of a high-fidelity Computer-Aided Design (CAD) model. The most important results are that the pressure rise in the valve closure is significant, 25.47 m (72.8% overshoot), and the system has a damping ratio of 0.744. The recovery potential has been calculated as 116.51 kWh/day with a recovering efficiency of 38.7 percent, which provides an economically viable payback period of 2.9 years. The model that is validated offers an important tool to predict the PAT behavior in real networks.