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See detailField Study on the Energy Consumption of School Buildings in Luxembourg
Thewes, Andreas UL; Maas, Stefan UL; Scholzen, Frank UL et al

in Energy & Buildings (2014)

Buildings account for 40 % of total energy consumption and 35 % of the total CO2 emitted in the EU. In consequence, there is an enormous energy saving potential and the European Union requires from all EU ... [more ▼]

Buildings account for 40 % of total energy consumption and 35 % of the total CO2 emitted in the EU. In consequence, there is an enormous energy saving potential and the European Union requires from all EU member states to save energy in this sector. Hence, reducing the energy consumption of buildings represents an essential component of environmental protection efforts. Furthermore, the new European directive 2010/31/EU requires that the member states tighten national standards and draw up national plans to increase the number of “nearly zero-energy buildings”. Well-planned energy-saving strategies presume knowledge of specific characteristics of the current national building stock. Therefore, the implementation of a process to support systematic data collection, classification and analysis of the energy consumption of buildings will become increasingly important during the coming years. In the field study described below we analyzed the energy consumption of 68 school buildings in Luxembourg. A separate collation of electricity and heat energy consumptions allowed to make a detailed analysis of specific energy parameters. Clustered according to energy sources, the new buildings were analyzed from a statistical point of view. We defined the energy relevant parameters such as energy standards, the purpose of use of the buildings or whether they had canteens. [less ▲]

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See detailStatic and dynamic testing on prestressed concrete slab elements with artificial bond deficiencies
Mahowald, Jean UL; Maas, Stefan UL; Waldmann, Danièle UL et al

in Proceedings of the 4th Bond in Concrete Conference, Vol. 1: General Aspects of Bond (2012)

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See detailDynamic damage identification using linear and nonlinear testing methods on a two-span prestressed concrete bridge
Mahowald, Jean UL; Maas, Stefan UL; Scherbaum, Frank UL et al

in Proceedings of the Third International Symposium on Life-Cycle Civil Engineering, IALCCE’12 (2012)

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See detailDamage Identification and Localisation Using Changes in Modal Parameters for Civil Engineering Structures
Mahowald, Jean UL; Maas, Stefan UL; Waldmann, Danièle UL et al

in Proceedings of the International Conference on Noise and Vibration Engineering (2012)

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See detailShear Stresses in Honeycomb Sandwich Plates: Analytical Solution, Finite Elemente Method and Experimental Verification
Wahl, Laurent UL; Maas, Stefan UL; Waldmann, Danièle UL et al

in Journal of Sandwich Structures & Materials (2012), 14(4), 449-468

Honeycomb composite structures are used in airplanes, railway cars and vehicles. The sandwich panels consist of two stiff face sheets of aluminium, which are bonded to a very lightweight honeycomb core of ... [more ▼]

Honeycomb composite structures are used in airplanes, railway cars and vehicles. The sandwich panels consist of two stiff face sheets of aluminium, which are bonded to a very lightweight honeycomb core of aluminium. Compared to normal plates, sandwich panels have a very high stiffness and simultaneously a low weight. The core of these structures is mainly subjected to shear stresses. The shear stresses depend strongly on the angle of the load application. The distribution and the level of the shear stresses are investigated using analytical calculations. The load direction which induces highest stresses in the honeycomb core is derived. This direction is not the W-direction, which is the most compliant one. When doing finite element simulations of honeycomb cores, often the core is homogenized in order to reduce the calculation time. In this article, some equations are derived in order to calculate the real shear stresses from the shear stresses of the homogeneous core. The equations are validated by finite element simulations and partially by tests. Three-point bending tests and additionally some Food Cart Roller Tests were conducted in order to test the panels in different angles. [less ▲]

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See detailShear stresses in honeycomb sandwich plates: Analytical solution, finite element method and experimental verification
Wahl, Laurent UL; Maas, Stefan UL; Waldmann, Danièle UL et al

in Journal of Sandwich Structures & Materials (2012), 4

Honeycomb composite structures are used in airplanes, railway cars and vehicles. The sandwich panels consist of two stiff face sheets of aluminium, which are bonded to a very lightweight honeycomb core of ... [more ▼]

Honeycomb composite structures are used in airplanes, railway cars and vehicles. The sandwich panels consist of two stiff face sheets of aluminium, which are bonded to a very lightweight honeycomb core of aluminium. Compared to normal plates, sandwich panels have a very high stiffness and simultaneously a low weight. The core of these structures is mainly subjected to shear stresses. The shear stresses depend strongly on the angle of the load application. The distribution and the level of the shear stresses are investigated using analytical calculations. The load direction which induces highest stresses in the honeycomb core is derived. This direction is not the W-direction, which is the most compliant one. When doing finite element simulations of honeycomb cores, often the core is homogenized in order to reduce the calculation time. In this article, some equations are derived in order to calculate the real shear stresses from the shear stresses of the homogeneous core. The equations are validated by finite element simulations and partially by tests. Three-point bending tests and additionally some Food Cart Roller Tests were conducted in order to test the panels in different angles. [less ▲]

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See detailIntegrative analysis of the energy flow in a steel plant and a comprehensive approach to increase the energy efficiency
Tarres Font, Joana UL; Maas, Stefan UL; Scholzen, Frank UL et al

in Proceedings METEC InSteelCON 2011, Düsseldorf Germany, CCD Congress Center, Düsseldorf, 27.06-01.07. (2011, July)

Steel industry is a highly intensive energy consumer. The energy used by the studied electric steelmaking plant could supply 25,000 households with thermal energy and 100,000 households with electrical ... [more ▼]

Steel industry is a highly intensive energy consumer. The energy used by the studied electric steelmaking plant could supply 25,000 households with thermal energy and 100,000 households with electrical energy. Increasing the energy efficiency of a steel plant will not only have impact in the reduction of greenhouse emissions but also in an increase of the competitiveness of the plant. A Luxembourgish steel plant is studied in detail and several options for energy savings are identified. Promising energy efficiency gains can be achieved by the optimization of the electric arc furnace and the reheating furnaces and by the improvement of the logistics between the continuous casting and the reheating furnace. The possibilities of energy recovery for heating purposes and for the generation of electricity with ORC- (Organic Rankine Cycle) or KALINAtechnologies are studied. In addition there is the opportunity to deliver hot water to a near district-heating system using otherwise lost energy and creating regional synergies. Nevertheless there is a need to develop a comprehensive and integrative approach to find a good overall solution instead of treating each step separately. The University of Luxembourg in collaboration with a Luxembourgish steel plant is developing a methodology to assess the technical, economical and environmental aspects of each solution. The objective is to assist in the decision-making in the company’s energy efficiency strategy and to perform a comparative analysis of the different solutions in order to propose an optimized plant, based on its feasibility due to local restrictions and different energy price scenarios. This ideal plant will be composed of individual elements, which proved their effectiveness in different real plants, so that the approach stays applied [less ▲]

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See detailFatigue in Aluminium Honeycomb-core Plates
Wahl, Laurent UL; Zürbes, Arno UL; Maas, Stefan UL et al

in Benchmark: The International Magazine for Engineering Designers & Analysts (2011), (January), 26-32

Honeycomb composite lightweight structures made of aluminium or aramid fibres are used in airplanes, railway carriages and automobiles. These structures are subjected to dynamic loading but hardly any ... [more ▼]

Honeycomb composite lightweight structures made of aluminium or aramid fibres are used in airplanes, railway carriages and automobiles. These structures are subjected to dynamic loading but hardly any fatigue properties of the honeycomb core exist in current literature. Hence here a theoretical and experimental approach is presented. [less ▲]

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See detailInfluence of environmental changes on modal characteristics
Waldmann, Danièle UL; Bungard, Volker UL; Mahowald, Jean UL et al

in Federation for Structural Concrete (fib) (2011)

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See detailEntwicklung von hybriden Wärmedämmsteinen aus LAC
Leufgens, Nadine UL; Waldmann, Danièle UL; Maas, Stefan UL et al

in Mauerwerk (2010), 14(1), 10-18

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See detailAmbient Vibration and Forced Excitation Tests of a Composite Bridge: Environmental influences and nonlinear effects on the dynamic properties
Bungard, Volker UL; Mahowald, Jean UL; Waldmann, Danièle UL et al

in Proceedings of the International Conference on Noise and Vibration Engineering, ISMA (2010)

Detailed reference viewed: 67 (18 UL)
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See detailComparison of linear and nonlinear static and dynamic behaviour of prestressed and non-prestressed concrete slab elements
Mahowald, Jean UL; Bungard, Volker UL; Maas, Stefan UL et al

in Proceedings of the International Conference of Noise and Vibration Engineering (2010)

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See detailThermal comfort of a new university building in Luxembourg with passive cooling
Thewes, Andreas UL; Maas, Stefan UL; Scholzen, Frank UL et al

in Thermal comfort of a new university building in Luxembourg with passive cooling (2010)

The new Luxembourgish university buildings should comply with a low energy standard, which was defined for typical offices and smaller lecture rooms by a thermal end-energy lower than 14 kWh/m3a and an ... [more ▼]

The new Luxembourgish university buildings should comply with a low energy standard, which was defined for typical offices and smaller lecture rooms by a thermal end-energy lower than 14 kWh/m3a and an electricity use for HVAC and lighting of max. 6 kWh/m3a. Consequently it was necessary to find ways to avoid the need for mechanical ventilation and air-conditioning. The heat consumption was minimized by an air-tight and well insulated building envelope. A difficulty was posed by special outside façade elements which were set-up as a grid over the complete outer surface as an architectural element. To prevent the risk of overheating during summer, it is necessary to reduce the solar gains by optimizing the window sizes and the glazing types, as well as through the installation of movable indoor shading elements. Nevertheless enough daylight should enter the rooms to limit the consumption of electricity for artificial lighting. Hence detailed dynamic simulations were performed using TRNSYS and TRNFLOW to ensure thermal comfort without active cooling. The effective electricity consumption of a newly installed state-of-the-art lighting system, including presence detectors and daylight controllers for dimming, was measured in a test installation to determine the internal loads by lighting. Radiation and illuminance measurements were performed on sample elements of the façade grid. The results were used to verify the daylight simulations and to analyze the benefits of daylight controllers. Several iterative steps were taken to gradually improve the building by introducing different modifications, e.g. reduction of the window sizes, installation of a lighting control system, improving the night ventilation and effective use of the thermal inertia of the building. [less ▲]

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See detailComparison of static behaviour and nonlinear vibration characteristic of gradually damaged prestressed concrete slabs and reinforced concrete beams
Bungard, Volker UL; Waltering, Markus UL; Waldmann, Danièle UL et al

in Proceedings of the International Conference on Experimental Vibration Analysis for Civil Engineering Structures (2009)

Detailed reference viewed: 44 (14 UL)