Browsing by Author "Carrascal, A."
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Item Kerf modelling in abrasive waterjet milling using evolutionary computation and ANOVA techniques(2012) Alberdi, A.; Rivero, A.; Carrascal, A.; Lamikiz, A.; FABRIC_INTEL; SGMany researchers demonstrated the capability of Abrasive Waterjet (AWJ) technology for precision milling operations. However, the concurrence of several input parameters along with the stochastic nature of this technology leads to a complex process control, which requires a work focused in process modelling. This research work introduces a model to predict the kerf shape in AWJ slot milling in Aluminium 7075-T651 in terms of four important process parameters: the pressure, the abrasive flow rate, the stand-off distance and the traverse feed rate. A hybrid evolutionary approach was employed for kerf shape modelling. This technique allowed characterizing the profile through two parameters: the maximum cutting depth and the full width at half maximum. On the other hand, based on ANOVA and regression techniques, these two parameters were also modelled as a function of process parameters. Combination of both models resulted in an adequate strategy to predict the kerf shape for different machining conditions.Item Kerf profile modelling in Abrasive Waterjet milling(Trans Tech Publications Ltd, 2012) Alberdi, A.; Rivero, A.; Carrascal, A.; Lamikiz, A.; FABRIC_INTEL; SGThe Abrasive Water Jet milling process is demonstrated to be an efficient technology for milling low machinability materials. Although its capability is demonstrated, the industrial application of this technology requires a depth control, for which a work focused in process modelling is needed. This research work introduces a model to predict the kerf shape in AWJ slot milling in Aluminium 7075-T651 in terms of four important process parameters: pressure, abrasive mass flow rate, stand-off distance and traverse feed rate. A hybrid evolutionary approach was employed for modelling the profile through two parameters: the maximum cutting depth and the full width at half maximum. Both the maximum depth and the width were also modelled as a function of aforementioned process parameters based on Analysis of Variance and regression techniques. Combination of two models resulted in an adequate strategy to predict the kerf shape for different machining conditions.Item A novel optimization algorithm for efficient economic dispatch of Combined Heat and Power devices(2016-01-01) Perea, E.; Ruiz, N.; Cobelo, I.; Lizuain, Z.; Carrascal, A.; DIGITAL ENERGY; POWER SYSTEMS; Tecnalia Research & InnovationCombined Heat and Power (CHP) units produce heat to warm living spaces, supply hot water and generate electricity. Their normal operation is determined by the building thermal demand. These systems supply hot water on demand from hot water storage tanks avoiding intermittent operation of the machines. A method based on a novel control algorithm is presented to optimize the operating costs of one or a set of CHP units in either commercial or residential buildings. The algorithm uses hot water storage tanks to schedule the daily operation of the CHP devices maximizing the benefits of the electricity that is generated, while ensuring that the heat demand is covered. This is especially relevant for regulatory environments with Time of Use tariffs for electricity. The method comprises an optimization algorithm that minimizes the value of a target function. The target function includes a series of weights that penalize the violation of certain constraints. The outputs of the optimization algorithm define the operating set points of CHP unit/s. The results of the case study simulations demonstrate that the proposed implementation of the algorithm can achieve cost effective savings. Finally, the successful operation of the algorithm is demonstrated in a real building installation.