Predição de bombas funcionando como turbinas em toda a faixa de operação: estudo de caso de uma rede de distribuição de água

Abstract

Nowadays, the importance of reducing energy costs and/or obtaining alternative forms of generation has increased more and more. In this context, pumps working as turbines (BFT) emerge as a sustainable alternative for energy generation taking advantage of the hydraulic potential of a location. However, the adversity found is related to the BFT operating range in turbine mode. This work aims to theoretically determine the operating range of pumps working as turbines of pumps selected to work as pressure reducing valves (PRV) in the water supply system (SAA) of Vila Permanente, in Tucuruí. Three experimental studies were evaluated and the methods of Sharma & Williams (1995), Yang et al. (2012) and Alatorre-Frenk (1994) to achieve the PATs head (Ht) and flow (Qt) prediction results in turbine mode at the best efficiency point (BEP); after that, the method developed by Rossi (2019) was applied, which works outside the entire operating range of the BFT, combined with the methods in the BEP to obtain the characteristic curves Q x H (flow x head) and Q x η ( flow x efficiency) of the BFT in turbine mode; and finally, the results obtained through the methods were compared with the results of experimental studies, so that the best combination of methods was selected. Then, with the height and flow values of the pressure points in the SAA of Vila Permanente, centrifugal pumps were selected to work as turbines, applying the best combination of method and then obtaining the characteristic curves Q x H (flow x head) and Q x η (flow x efficiency) of the BFT in turbine mode, in order to reveal various points where the BFT can operate; in addition to energy recovery calculations with values in KW per day, month and year. In water supply systems, energy costs are excessive and it is common to use pressure reducing valves at points where this reduction is necessary to ensure the right circumstances for the transport of water in the pipeline. In this way, it is understood that there is a waste of energy that could be used in the system itself.