Examinando por Autor "Arias-Rosales, A."

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    Nominal energy optimisation method of constrained battery packs through the iteration of the series-parallel topology
    (John Wiley and Sons Ltd, 2017-10-10) Fernández-Montoya, M.; Arias-Rosales, A.; Osorio-Gómez, G.; Mejía-Gutiérrez, R.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
    The design of a battery pack commonly deals with high performance goals and challenging constraints in terms of cost, volume or weight. One of the most crucial variables to maximise is the nominal energy, which depends on the number of discrete battery cells that can be allocated and their individual technical specifications. This work proposes a systematic method to optimise the nominal energy of a constrained battery pack from the perspective of the series-parallel topology. A mathematical and graphical characterisation is presented on how the main battery's variables are related to a topology bounded to discretisation procedures. It was theoretically found that the effects of rounding the values of the topology may lead to a considerable loss of potential nominal energy, a risk that increases linearly with the number of series. The behaviour of the battery is assessed under nominal conditions and under the event of a cell failure. The theoretical analysis suggests that the detrimental effects due to an open-circuit increase as the number of series increases, while it is the opposite in the case of a shorted cell. The method is satisfactorily implemented in the development of two different battery packs for solar competition cars with limiting regulations. The candidate topologies outperformed the nominal energy of topologies defined without the method in up to 5%. It was also found that selecting an energy-maximising topology is not always the most convenient choice, because other variables may be of interest and are dependent on the topology as well. The method is of great use to guide the topology definition process in early theoretical stages, which is usually a compromise between allocating as much cells as possible within constraints, and approaching other performance goals such as a given nominal voltage or capacity. Copyright (c) 2017 John Wiley & Sons, Ltd.
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    Wind turbine selection method based on the statistical analysis of nominal specifications for estimating the cost of energy
    (Elsevier Ltd, 2018-10-15) Arias-Rosales, A.; Osorio-Gómez, G.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
    Wind turbine selection is a critical engineering problem in the overall cost-effectiveness of a wind project. With the wide spreading and democratization of wind energy technologies, non-expert stakeholders are being faced with the challenge of selecting among very different wind turbines. As a comprehensive indicator, the cost of energy can serve as a guide, but reportedly misleading publicity and commonly unavailable information render its calculation more inaccessible and less reliable. Accordingly, this work proposes a method to compare wind turbines, on the basis of the cost of energy, from only nominal specifications and a standard characterization of the local wind conditions. For this endeavor, it was identified that two key variables are not usually available at a preliminary stage: the total efficiency and a feasible hub height. Through a systematic statistical analysis of the trends in a constructed dataset of 176 turbines, it was possible to establish regression models for the estimation of both variables. These models were tested in a validation set and their estimations were found to correctly characterize the central trend of the data without significant deviations. The uncertainty related to the use of both models was addressed by analyzing the 95% Prediction Intervals and the stochastic rank dominance. The established statistical models were then used as the core of the proposed selection method. When the available information is limited or not trustworthy, the steps of the method can be followed as an approach to estimate the cost of energy of a given horizontal axis wind turbine in a given location. © 2018 Elsevier Ltd