Simulação do uso de bombas com velocidade variável em processos de saneamento

Abstract

The pursuit of energy efficiency and sustainability in sanitation systems motivated this study, which investigated the use of variable-speed centrifugal pumps (VSCPs) in water supply, sewage systems, and urban drainage processes. The main objective was to develop a computational tool to simulate the behavior of these pumps under different operational conditions, comparing their performance with constant-speed pumps (CSPs). The methodology included mathematical modeling based on hydrodynamic similarity laws and the implementation of a C++ algorithm, validated through comparison with reference data. Twenty one scenarios were analyzed, varying the initial flow rate (Qₘ) from 200 to 800 m³/h and the flow variation amplitude (Aq) from 20 to 60 m³/h, over 24-hour periods. Results demonstrated that VSCPs are significantly more efficient at low flow rates (Qₘ ≤ 400 m³/h), achieving energy savings between 19% and 43%. However, at higher flow rates (Qₘ ≥ 500 m³/h), variable-speed operation became less advantageous, resulting in increased energy consumption (up to 154% in extreme cases). The reduction in power consumption at low-speed regimes, combined with the flexibility to adjust flow rates without throttling losses, justifies the adoption of VSCPs in systems with fluctuating demands. It was concluded that variable-speed technology is feasible for energy optimization in specific contexts, particularly in sanitation applications with moderate demand variations. The developed tool enables the analysis of real-world scenarios, supporting technical decision-making and education in sanitary and environmental engineering.