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37 51 20 1 ; OJS ; [EN] One of the main problems of the water treatment plants is the high energy consumption they have to face. Therefore, reducing energy consumption is an imperative objective for these facilities. This work proposes a mathematical programming model for the capacity planning and the management of water treatment plants using dilution process that will reduce the energy consumption in the aeration phase. This model presents, as a novelty, the inclusion of the time variable, generating a quasi-stationary model that has been applied to a real case study. ; [ES] Uno de los principales problemas de las plantas de tratamiento de agua es el elevado consumo energético al que tienen que hacer frente. Por ello, reducir el consumo energético es objetivo prioritario para dichas instalaciones. Este trabajo propone un modelo de programación matemática para la planificación de la capacidad y gestión de instalaciones depuradoras de agua, que mediante dilución, re-duzca el consumo energético en la fase de aireación. Dicho modelo presenta como novedad la inclusión de la variable tiempo, generando un modelo cuasiestacionario, que ha sido aplicado a un caso real de estudio. Colomina, M.; Pérez Sánchez, M.; Sanchis, R.; Díaz-Madroñero Boluda, FM. (2020). Análisis de la capacidad necesaria en los procesos de tratamiento de aguas mediante programación matemática. Un caso de estudio. Economía Agraria y Recursos Naturales - Agricultural and Resource Economics. 20(1):37-51. https://doi.org/10.7201/earn.2020.01.02

1 21 3 ; S ; Simao, M.; Pérez-Sánchez, M.; Carraveta, A.; López Jiménez, PA.; Ramos, HM. (2018). Velocities in a Centrifugal PAT Operation: Experiments and CFD Analyses. Fluids. 3(1):1-21. https://doi.org/10.3390/fluids3010003 ; [EN] Velocity profiles originated by a pump as turbine (PAT) were measured using an ultrasonic doppler velocimetry (UDV). PAT behavior is influenced by the velocity data. The effect of the rotational speed and the associated flow velocity variations were investigated. This research focuses, particularly, on the velocity profiles achieved for different rotational speeds and discharge values along the impeller since that is where the available hydraulic power is transformed into the mechanical power. Comparisons were made between experimental test results and computational fluid dynamics (CFD) simulations. The used CFD model was calibrated and validated using the same conditions as the experimental facility. The numerical simulations showed good approximation with the velocity measurements for different cross-sections along the PAT system. The application of this CFD numerical model and experimental tests contributed to better understanding the system behavior and to reach the best efficiency operating conditions. Improvements in the knowledge about the hydrodynamic flow behavior associated with the velocity triangles contribute to improvements in the PAT concept and operation. The authors wish to thank to the project Reducing Energy Dependency in Atlantic Area Water Networks (REDAWN) EAPA_198/2016 from INTERREG Atlantic Area Programme 2014-2020 and CERIS (CEHIDRO-IST) and the Hydraulic Laboratory, for the support in the conceptual developments and the experiments on PATs. The authors also thank the program to support the academic career of the faculty of the Universitat Politecnica de Valencia 2016/2017 in the project "Maximization of the global efficiency in PATs in laboratory facility" of the second author. Yang, S.-S., Derakhshan, S., & Kong, F.-Y. (2012). Theoretical, numerical ...

302 311 208 ; S ; [EN] The use of pumps working as turbines (PATs) connected to the electric system, in the replacement of pressure reduction valves to reduce the excessive pressure in water distribution networks, have been studied for the last years. The introduction of PATs is very important in the water-energy nexus to promote the increase of the energy savings. As consequence, the majority of the water systems does not have access to the electrical grid and, therefore, the need to study the PATS operation off-grid is necessary. In this line, the novelty of this research is the application and optimization of a PAT in water systems when the recovery solution is off-grid type. To operate correctly, the induction machine requires an external source of reactive power, which is typically provided by the electrical grid. To supply the required reactive power, a bank of capacitors is installed at the machine terminals, so-called self-excited induction generator (SEIG). The analytical model, simulation and experimental works were performed, to analyse the SEIG behaviour. The results were applied in a SEIG-PAT system obtaining the global efficiency of the system for different speeds and loads. The global efficiency decreases 47% when off-grid operation, showing the need to optimize the electrical parameters of the generator to operate as off- grid with acceptable efficiency levels. In this framework, a tuning methodology for the SEIG capacitor bank values was developed to be automatically adjusted according to the operating point of the PAT to maximize its efficiency. This research is supported by Academic program career of the faculty of the Universitat Politecnica de Valencia 2016/2017 in the project "Maximization of the global efficiency in PATs in laboratory facility" and by FCT, through IDMEC, under LAETA, project UID/EMS/50022/2013. Besides, the authors wish to thank to the project REDAWN (Reducing Energy Dependency in Atlantic Area Water Networks) EAPA_198/2016 from INTERREG ATLANTIC AREA PROGRAMME 2014-2020 ...