• Energy Research
• Restricted close
• BE close
• IN close
• SA close
• CM close

Abstract Resulting from a Ph.D. research a Vehicle Simulation Programme (VSP) is proposed and continuously developed. It allows simulating the behaviour of electric, hybrid, fuel cell and internal combustion vehicles while driving any reference cycle [Simulation software for comparison and design of electric, hybrid electric and internal combustion vehicles with respect to energy, emissions and performances, Ph.D. Thesis, Department Electrical Engineering, Vrije Universiteit Brussel, Belgium, April 2000]. The goal of the simulation programme is to study power flows in vehicle drive trains and the corresponding component losses, as well as to compare different drive train topologies. This comparison can be realised for energy consumption and emissions as well as for performances (acceleration, range, maximum slope, etc.). The software package and its validation are described in [J. Automot. Eng., SAE IEE 215 (9) (2001) 1043L]. Different hybrid and electric drive trains are implemented in the software [Views on hybrid drive train power management strategies, in: Proceedings of the EVS-17, Montreal, Canada, October 2000]. The models used for the energy sources like fuel cells, batteries, ultracapacitors, flywheels and engine-generator units will be discussed in this paper in three stages: first their functionality and characteristics are described, next the way these characteristics can be implemented in a simulation model will be explained and finally some calculation results will illustrate the approach. This paper is aimed to give an overview of simulation models of energy sources for battery, hybrid and fuel cell electric vehicles. Innovative is the extreme modularity and exchangeability of different components functioning as energy sources. The unique iteration algorithm of the simulation programme allows to accurately simulate drive train maximum performances as well as all kind of power management strategies in different types of hybrid drive trains [IEEE Trans. Veh. Technol., submitted for publication].

Life Cycle Assessment is a tool to assess the environmental impacts and resources used throughout a product's life cycle, i.e., from raw material acquisition, via production and use phases, to waste management. The methodological development in LCA has been strong, and LCA is broadly applied in practice. The aim of this paper is to provide a review of recent developments of LCA methods. The focus is on some areas where there has been an intense methodological development during the last years. We also highlight some of the emerging issues. In relation to the Goal and Scope definition we especially discuss the distinction between attributional and consequential LCA. For the Inventory Analysis, this distinction is relevant when discussing system boundaries, data collection, and allocation. Also highlighted are developments concerning databases and Input-Output and hybrid LCA. In the sections on Life Cycle Impact Assessment we discuss the characteristics of the modelling as well as some recent developments for specific impact categories and weighting. In relation to the Interpretation the focus is on uncertainty analysis. Finally, we discuss recent developments in relation to some of the strengths and weaknesses of LCA.

Abstract Highly three-dimensional and complex flow structure within the tip gap of an axial flow turbine is a substantial source of aerodynamic loss and heat transfer due to the interaction between the tip leakage vortex, secondary flows and the main passage flow. Most contemporary shroudless high pressure (HP) turbine designs employ squealer tips for durability, structural, aerodynamic design and heat transfer reasons. The present research deals with the influence of squealer width and height on the aerothermal performance of a HP turbine blade. In this study, four different squealer heights and seven squealer width values are investigated using a computational approach for an axial turbine blade depicting an E 3 “Energy Efficient Engine” design. The specific HP turbine airfoil under investigation is identical to the rotor tip profile of the Axial Flow Turbine Research Facility (AFTRF) of the Pennsylvania State University. Numerical calculations are performed by solving the three-dimensional, steady and turbulent form of the Reynolds-Averaged Navier-Stokes (RANS) equations. A two-equation turbulence model, Shear Stress Transport (SST) k-ω is used in the present set of calculations. The current numerical predictions show a very good agreement with the extensive aerodynamic measurements obtained in the nozzle guide vane passages of AFTRF. The results indicate that determining proper squealer width and height is crucial to obtain better aerothermal performance in the form of reduced aerodynamic loss and heat transfer to the tip platform. Extensive numerical analysis within the tip gap reveals that increasing squealer height and reducing squealer width increases cavity volume leading to enlarged vortical structures near the pressure side and suction side of the cavity. Because of this enhanced vortical activity in the tip cavity, a blockage to the incoming pass-over flow is introduced and as a result tip leakage mass flow rate is reduced. While the tip leakage flow rate tends to decrease with increased height and reduced width, there is a strong effect from the squealer width and height combination due to the presence of complex interactions in the tip gap region. From a heat transfer point of view, decreasing squealer width and increasing squealer height noticeably reduces the overall Nu ‾ on the blade tip platform. Nu ‾ on the cavity floor, blade tip and squealer side walls are reduced depending on the increasing height and decreasing width values.

Abstract In order to develop a deeper understanding of the behaviour of commercial automotive lithium-ion pouch cells under short-circuiting conditions, two scenarios were experimentally investigated and compared. Firstly, experiments were conducted by internally shorting 15 Ah cells by full nail penetration using three different nail materials; copper, steel and plastic. A second set of experiments involved externally shorting the cell tabs using an external circuit with a range of resistance values. In both scenarios the cell electrical and thermal response were determined by the shorting resistance. In the case of nail penetration there was a clear distinction between the outcome of the conducting and non-conducting nails, although the outcome using conducting nails suffered from poor reproducibility. The poor reproducibility was attributed to the variation in the contact resistance between the nail and the cell layers. Correlating the outcome of both tests can be used to estimate the shorting resistance and construct the current profile during nail penetration test.

Sustainable agriculture leads today to important questions about the diversification of agricultural production and sources of income for farmers, the use of rural and arable land for food and non-food crops, the contribution of agriculture to climate change fighting and the supply of renewable energy. Bioenergy from agriculture is at the heart of these concerns, integrating sustainable development key components: environment and climate change, energy economics and energy supply, agriculture, rural and social development. The lack of primary and reliable data on bioenergy externalities from agriculture and the lack of decision-making tools are important non-technological barriers to the development of bioenergy from agriculture on a large scale, and, consequently, to the achievement of the national and regional objectives of sustainable development with respect to greenhouse gas mitigation, secure and diversified energy supply, rural development and employment and the future of agriculture. Furthermore, the recent worldwide controversies about transport biofuels, food shortages and increasing prices have demonstrated the urgent need for sustainability criteria applied to biofuels and bioenergy. Within this current sustainable development framework, a project entitled TEXBIAG integrating experts from 4 research institutions is financed by the Belgian Science Policy. The final objective of this project is to lead to an actual and significant contribution of bioenergy from agriculture to the mitigation of greenhouse gas emissions, to a secure and diversified energy supply and to farmers' incomes and rural development. To reach this final objective, the project develops three specific tools: (1) a database of primary quantitative data related to environmental and socio-economic impacts of bioenergy from agriculture integrating biomass logistics; (2) a mathematical model monetizing bioenergy externalities from agriculture; and (3) a prediction tool assessing the impacts of political decisions made in the framework ofthe development of bioenergy from agriculture on different economic sectors (energy, agriculture, industry, and environment). An integrated interface tool will be programmed where access to and update of the three tools will be prepared. The project methodology will be conducted for a given number of scenarios with sensitivity analysis wherever possible. The three main target groups that will benefit from the project are: the government officials and policy makers in the field of agriculture, energy and environment in Belgium and its two main regions, the small, medium and large energy companies and the agricultural sector

The Poster proposes a research agenda for the creation of knowledge about the potential of Digital Product Passports (DPPs) as a means to promote the sustainability of the textiles sector. Analysis is called for to transition to a more sustainable society by focusing on the 1) Textiles ecosystem: relevant stakeholders and their interrelationships 2) Trust, transparency, reliability, sustainability, and information 3) DPPs as an information system 4) Data requirements for DPPs and 5) The societal impacts of DPPs.

The technological development of preparing bio-oil from low-temperature hydrothermal conversion of agricultural and forestry waste has positive significance for alleviating the shortage of oil energy supply and reducing environmental pollution. This paper selects typical oxides (Al2O3, CeO2, MgO, SiO2, TiO2, and ZnO) as catalysts to set up a low-temperature (220 °C) hydrothermal conversion process of cotton stalk containing pretreatment processes including chopping. For moderate amplification estimation, lab-scale experimental data is used as a benchmark for calculation, and the functional unit for this study is set to be a 1 kg bio-oil product. The results suggest that the cerium dioxide-involved process with the highest bio-oil yield and highest synthetic consumption, and the silica-involved process with the lowest bio-oil yield, caused the highest environmental impact, resulting in greenhouse gas (GHG) emissions of 67.729 kg CO2e/kg and 60.001 kg CO2e/kg, respectively. It indicates that catalysts need to consider the balance between synthetic consumption and catalytic performance. Magnifying lab-scale data to an industrial scale using scale-up frameworks introduces a low model uncertainty, as the practical value had little effect on the overall evaluation results. However, existing equipment data should be used to reduce the uncertainty of the model itself. The environmental sustainability of bio-oil production by low-temperature hydrothermal liquefaction still needs to be improved, especially by catalyst recovery and bio-oil yield improvement.

Abstract Thermochemical energy storage (TCS) based on gas-solid reactions constitutes a promising concept to exploit reaction enthalpies for thermal energy storage. This concept facilitates the development of efficient storage solutions with higher energy densities compared to widely investigated sensible and latent thermal energy storage systems. Multivalent metal oxides are capable of undergoing a reversible redox reaction at high temperatures, which is why those storage materials are considered particularly suitable for the operating temperature range of concentrated solar power plants with central receiver systems to increase the total plant efficiency and ensure dispatchability of electricity. In the scope of this work a granular manganese-iron oxide with a Fe/Mn molar ratio of 1:3 has been selected as a potentially suitable storage material, which is non-toxic, abundant and economical. For this reason a preparation route from technical grade raw materials has been chosen. The reversible redox reaction is investigated with respect to the thermodynamic and kinetic characteristics by means of simultaneous thermal analysis in dynamic and isothermal series of measurements. Those revealed that the observed presence of a strong divergence of the reactive temperature range from the actual thermodynamic equilibrium can mainly be attributed to kinetic limitations. Expressions for the effective reaction rates are deduced from experimental data for the reduction and oxidation step, describing the dependence of the reaction rate on temperature and oxygen partial pressure, respectively. The expressions are valid for the temperature ranges in proximity to the equilibrium, which are relevant for the targeted operating conditions of the storage reactor in air. The storage material provides good cycling stability in terms of reversibility and widely maintained reactivity throughout 100 redox cycles in air. Future work comprises material modifications, which are expected to further enhance the mechanical stability of the particles. Overall, the manganese-iron oxide of the chosen composition exhibits a redox reactivity practical for regenerator-type storage systems combining a high temperature TCS zone and a lower temperature non-reactive zone merely used for sensible thermal energy storage.