A New Device for Pressure Control and Energy Recovery in Water Distribution Networks

Abstract

The potential energy of the water in Water Distribution Networks (WDNs) usually exceeds the amount needed for delivery and consumption and, at the present time, it is mainly dissipated through Pressure Reducing Valves (PRVs) or Open Water Tanks. The present study suggests the use of a new energy-producing device, a Cross-flow turbine with positive outlet pressure named PRS (Power Recovery System), which can provide the same service as PRVs and water tanks, with additional significant hydropower production. After a short presentation of the PRS, the management rules of the proposed device are laid out, according to two possible modes. In the 'passive' mode, the piezometric level downstream of the turbine is fixed at the sought after value, in the 'active' mode, the discharge is regulated according to the required value. The design criterion is then presented, based on a simple relationship linking dimensionless numbers. A PRS is finally designed for a typical water distribution network, serving the city of Palermo (Italy). The resulting cost-benefit analysis is compared with a similar one carried out in previous work for a regulation system based on the use of a Pump As Turbine (PAT). The comparison shows the improvement obtained by the use of the PRS, consisting of higher energy production, as well as lower construction and installation costs.

A Bi-Objective Approach for Optimizing the Installation of PATs in Systems of Transmission Mains

“…On the other hand, attempts have recently been made to recover energy from water networks and thus to compensate part of the intensive energy consumption associated with water supply. Energy recover can be accomplished by installing devices such as hydro-turbines [3][4][5][6][7] or pumps operating in reverse mode, also called pumps as turbines (PATs) [8][9][10][11][12], within pressurized pipes. Though featuring lower efficiencies than hydro-turbines, PATs feature much lower costs, thus offering themselves as a very cost-effective solution for energy recovery from water distribution networks.…”

Comparison of Algorithms for the Optimal Location of Control Valves for Leakage Reduction in WDNs

“…In fact, if service pressure is reduced without violating pressure constraints for water supply, positive effects arise without the service effectiveness being affected. The active control of service pressure can also be performed through devices that enables electric power generation [4,5].…”

Innovative mini-hydro device for the recharge of electric vehicles in urban areas

“…In the last few years, interesting and numerous efforts have been dedicated to unravelling the knot and to define general equations able to transpose the characteristic curve of a pump to the correspondent in reverse mode, adopting experimental set-up [18,19], computational fluid dynamics applications (CFDs) [20][21][22], literature data [23], or proposing new devices [24]. Jain and Patel [25] presented a detailed state of the art about this aspect; several researchers, with the aim to analyze the behavior of a pump in a turbine mode, had defined several and sometimes really different relations for the prediction of PAT efficiency, based on specific speed in pump mode.…”