Energy Recovery in Water Systems by PATs: A Comparisons among the Different Installation Schemes

Pressure reducing valves are frequently used within water distribution networks to reduce pressure values. The use of a pump working as a turbine (PAT) to recover the dissipated energy is generally considered the most cost-effective solution, but PATs are not provided with any regulation device. Thus, in presence of variable hydraulic conditions, a regulation system has to be inserted in the power plant to obtain the requested backpressure value. A comparison among the feasible regulation systems for PAT reg- ulation is discussed and the optimal solution is found by means of the power plant effectiveness, combining system capability, flexibility and reliability.