No abstract

Tight-binding molecular dynamics calculations have been carried out to study the SiO desorption at high temperature during the oxidation of Si(111) surface. In our model, the on-top site of SiO at the Si(111) surface was heated partially on purpose. The high wagging and stretching energies related to the SiO are considered to be the origin of SiO desorption for the present calculations. Vibrational frequencies at the oxygen adsorption site on Si(111) surface and both rovibrational and translational energies of desorbed SiO molecule were calculated and compared with the experimental results. The SiO molecule desorbed at the thermal equilibrium state which is in agreement with the experimental results.

Over their whole life cycle, buildings are responsible for high environmental impacts and require critical financial resources. Decisions in the early design phase have a significant impact on both. This study aims to develop a visual decision support tool for architects in order to integrate an environmental and economic life cycle approach for dwellings. To evaluate the environmental impacts of the building design, the tool uses the Belgian LCA method, ‘Environmental Profile of Building Elements’. This method translates 17 environmental indicators in environmental costs by considering the cost to avoid, reduce or compensate the effects to a level that is bearable. The tool allows to combine these life-cycle environmental costs (LCEC) with Life Cycle financial Cost (LCFC). To estimate the operational energy use of the building, the “dynamic Equivalent Heating Degree Day (dEHDD)” method is used. This method allows for fast and relatively accurate heating energy estimations in the early phase, based on a limited number of input data. The tool visualises the results in a graphical way which can be easily understood by architects. Even more, visualisation is seen as a powerful communication tool to share information and ideas with all stakeholders.

No abstract

In recent decades, as a result of continuously increasing urbanization and climate change, energy saving has become a critical issue. Due to the high dwelling density, most compact urban areas have limited possibilities for natural ventilation combined with reduced solar radiation. As a consequence, a balance has to be found between reduced comfort and increased energy cost for cooling or heating. The aim of this study is to minimise the energy consumption and optimize thermal comfort of terraced houses in different urban patterns, by using natural ventilation and considering solar radiation. This study analyses different parameters on the level of buildings and urban layouts. The building characteristics include building sizes, window design, materials and internal wind permeability. The urban layouts consist of different building heights, setbacks and road widths. Energy consumption and thermal comfort are calculated by a dynamic simulation using EnergyPlus. Then the generic optimisation tool GenOpt is used to search for the lowest cost to reach a predefined minimum thermal comfort. Both the temperate climate in Belgium and the tropical climate in Vietnam were analysed to check the efficiency and robustness of the models. Conclusions are drawn for sketch design in the given contexts.