Rotational speed variation assessment of centrifugal pump-as-turbine as an energy utilization device under water distribution network condition

Abstract

Nowadays, to extend the application of clean energy sources, the utility of small power plants has been expanded and one of them is the potential utilization of water distribution networks (WDNs). By replacing pressure reducing valve (PRV) with a soft pressure regulating system (SPRS) the available hydraulic energy could be employed for generating electricity. A pump as turbine (PAT), considering its economic advantages and proper mechanical function, is a valuable option to be used in WDN. Since the use of PAT requires a precise understanding of how it operates under various hydraulic conditions, the lack of sufficient information in this area can be an obstacle to the expansion of PAT plants. In this paper, the results of a variable speed centrifugal pump installed in a WDN that has the task of regulating pressure and producing power were analyzed with the focus on the effects of speed variation on characteristic parameters. The findings showed that by incorporating a speed parameter in PAT descriptive relations, the prediction’s accuracy of the head, power and efficiency curves, respectively can be improved by 3.7%, 12.2% and 34.4%, compared to the nearest model. Provided correction relations help to improve estimations of PAT’s energy performance in the network.