Smart Grid Projects Outlook 2014

Smart grid projects are playing a key role in shedding light on how to move forward in this challenging transition. In 2011, therefore, the JRC launched the first comprehensive inventory of smart grid projects in Europe to collect lessons learned and assess current developments. The participation of project coordinators and the reception of the report by the smart grid community were extremely positive. It was therefore decided that the project inventory would be carried out on a regular basis so as to constantly update the picture of smart grid developments. This study is the 2013-2014 update of the inventory started out in 2011. The JRC’s 2013-14 Smart Grid database contains 459 smart grid R&D and D&D projects from all 28 European Union countries. Switzerland and Norway were studied together with the EU28 countries since they are present in a substantial number of projects with EU countries. Other 17 non EU countries are represented in the inventory by their participating organisations. The total investment of the smart grid projects amounts to €3.15 billion.JRC.F.3-Energy Security, Systems and Marke

Power transformer thermal analysis by using an advanced coupled 3D heat transfer and fluid flow FEM model. International ournal of Thermal Sciences

a b s t r a c t Thermal performance in oil-immersed power transformers is governed by the flow of oil, acting both as an electrical insulator and a medium for the transfer of heat generated in the core and windings toward the tank and the surrounding air. This paper presents the development of an advanced threedimensional (3D) finite element model for the coupled solution of heat transfer and fluid flow equations governing transformer thermal performance. The main advantages of the proposed method are: (i) no need to predefine the convection coefficients at the interfaces between the active part/tank walls and the circulating oil, (ii) detailed representation of specific transformer parts that play an important role in the accurate representation of oil flow and heat dissipation (such as winding cooling ducts and corrugated tank panels) through an automated design process, enhancing the model accuracy with the least possible computational effort and (iii) accurate definition of the transformer heat sources (core and windings loss). The proposed methodology provides an integrated tool for thermal simulation, able to predict detailed thermal distribution in a specific transformer, without requiring prior knowledge of nodal temperature or temperature gradient values

Daedalus – A software package for the design and analysis of airfoils

Summarization: A software package named Daedalus is presented for the design and analysis of airfoils. Daedalus is a collection of integrated geometry, analysis, optimization and visualization tools, which provide the ability to interactively construct and analyze standard airfoils using the NACA analytical equations and non-standard airfoils using the NURBS equations. Additionally, a database incorporating hundreds of airfoils is linked to Daedalus. Computational Fluid Dynamics (CFD) and mesh generation tools have been integrated, providing the ability to produce fast flow field calculations. Additionally, a Differential Evolution algorithm is embedded, in order to iteratively solve the inverse airfoil design problem, using a prescribed pressure (or velocity) distribution. Concerning the standard airfoil profiles, Daedalus supports various NACA-series and symmetrical biconvex airfoils. Airfoils are produced in the form of a distribution of points with variable density, in order to provide densely spaced points near the leading and trailing edges. Furthermore, by providing the coordinates and weights of the corresponding control points, the user can design non-standard section profiles using the NURBS equations. Additionally, the proposed software incorporates the ability of interpolating an existing airfoil using B-Splines polynomials. In this way a section described with a small number of surface points can be reconstructed with a desired density of points for producing acceptable computational meshes. Moreover, a new airfoil can be produced by slightly modifying an existing standard airfoil, by displacing the corresponding B-Splines control points of the interpolated initial airfoil. Besides the geometrical tools, Daedalus provides the capability of calculating the flow field around any airfoil, under prescribed flow conditions, using embedded mesh generation and analysis tools. By incorporating the geometrical design, the mesh generation and the flow analysis tools within the same software package, the airfoil design and evaluation procedure becomes automated, without the need of interaction and data transfer between different software packages. The above mentioned tools can be used in conjunction with a Differential Evolution optimizer, integrated within the software package, in order to solve the inverse airfoil design problem. The cost function to be minimized is the area of the difference between the target pressure distribution and the calculated one for each candidate solution.Παρουσιάστηκε στο: First South-East European Conference on Computational Mechanic

Freeform deformation vs. B-Spline representation in inverse airfoil design

Summarization: In this work FFD technique is compared to the classical parameterization technique using B-Spline curves by performing inverse airfoil design tests, with a Differential Evolution (DE) algorithm to serve as the optimizer. The criteria of the comparison between the two techniques are the achieved accuracy in the approximation of the reference pressure distribution and the convergence behavior of the optimization algorithm. Experiments are presented, comparing FFD to B-Spline techniques under the same flow conditions, for various numbers of design variables.Παρουσιάστηκε στο: 8th Biennial Conference on Engineering Systems Design and Analysi