Energy audit of irrigation networks

Abstract

The relationship between water and energy in water distribution systems (WDS) has been a growing concern among energy and water experts. Among the different strategies to improve water–energy efficiency in water distribution networks, energy audits are of paramount importance as they quantify water flow requirements, the amount of energy consumed to meet demand and leakage and friction losses. Previous work has presented the energy audit process for urban WDS and this energy audit is extended to irrigation networks here. This work analyses the most common types of irrigation emitters (sprinklers and pressure compensating and non-pressure compensating drippers), hydrant specifications, irrigation management systems (on-demand or rigid scheduled), and energy losses due to friction in pipes, control valves and irrigation hydrants. The energy audit does not assess whether management of the network is optimal, but analyses the energy consumption. Some of the performance indicators have already been defined for agricultural water networks, some are identical to those of urban WDS, but in addition, a new one is presented that disaggregates the energy dissipated into three terms, energy losses in pipelines, in hydraulic valves and in irrigation hydrants. These indicators show information necessary to better understand the performance of the irrigation network under study, to carry out a deep analysis of energy consumption and to allow for comparison with similar systems. The paper presents the analysis of a real case study conducted on the irrigation network of the garden of the Universidad Politécnica de Valencia.