Detailed Audit of the Energy Efficiency in Water Systems: New Performance Indices

Abstract

The proposed work aims at developing a new set of indices to carry out the energy audit of water systems. The new set consists of both supply and distribution indices and results from a global energy balance applied to a reference network. In this study, the energy audit of two case study networks is presented by the aid of the new proposed indices. Moreover, for each network, different scenarios are considered, differing in the management strategy proposed to increase the energy efficiency of the system. The comparison of the scenarios in terms of indices has allowed for evaluating the most efficient strategy to reduce the pressure exceeding within the network, among different solutions. According to the results, with reference to the case study distribution network, installing both pumps as turbines and pressure reducing valves represent the most efficient strategy, containing the excess pressure and also offering possibility for energy recovery. Moreover, with reference to the water supply system assumed as further case study network, the strategy exhibiting better values in terms of indices is represented by a direct pumping towards the downstream distribution network, instead of pumping towards an upper reservoir and using a valve or a turbine to dissipate the excess pressure. In this work, the proposed indices are demonstrated to be a useful tool for water managers to identify, among different solutions, the most effective intervention to increase the energy efficiency of water systems.