Damien Trigaux

Model for the environmental impact assessment of neighbourhoods

In order to move towards a sustainable built environment, modern cities need to be planned and organized differently, focussing not only on the characteristics of individual buildings but also on the relations between buildings and infrastructure works. Based on an existing Life Cycle Assessment (LCA) method for buildings, this paper proposes a model to assess the environmental impact of building clusters, together with the required road infrastructure. A hierarchic assessment structure, using the principles of the “element method for cost control” and a subdivision in different scale levels, is presented and methodological issues are discussed. To illustrate the methodology, abstract neighbourhood models are compared consisting of different dwelling types and the related amount of road infrastructure. The results revealed substantial environmental impact differences between the analysed alternatives, showing the importance of optimizing the layout and density of neighbourhoods.

Cost And Comfort Optimisation For Buildings And Urban Layouts By Combining Dynamic Energy Simulations And Generic Optimisation Tools

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.

An approach for handling environmental and economic conflicts in the context of sustainable building

When striving for sustainable buildings, the focus is often set on the optimization of the building environmental impact. In that perspective, the Life Cycle Assessment (LCA) method is widely used to calculate the environmental impact and through comparative studies, the preferred design options are chosen. As costs are however a very important issue in decision making, it is important to include costs in the analysis too. Although decisions are often only based on investment cost, we recommend considering also the life cycle cost (LCC) to guarantee long term affordability. This paper illustrates the importance of considering both aspects by discussing the optimisation of 16 representative residential buildings in Belgium from both an environmental and financial perspective. The question raises how to handle contradictions between the results of an LCA and LCC study of a building. The paper discusses and illustrates the promising approach of monetary valuation of environmental impacts. Recommendations are formulated based on the experience in the Belgian context.

Critical Analysis of Sustainability Scoring Tools for Neighbourhoods, based on a Life Cycle Approach

To achieve higher sustainability of steel reinforced concrete structures, their service life should be extended. When subject to chloride induced steel corrosion, time dependent repair works are most probably inevitable. Evidently, this results in extra concrete manufacturing and thus more environmental impact. Cracks offering direct pathways for the corrosion inducing substances play a very detrimental role in this. This paper presents the potential of using self-healing concrete to cope with this problem. By incorporating a polyurethane (PU)-based healing agent that is adequately released upon crack occurrence, chloride ingress is hindered substantially and onset of active corrosion is postponed. The required number of repair actions within 100 years could then drop to zero. Nevertheless, the implementation of a self-healing mechanism comes along with a higher initial cost and additional environmental impacts. Therefore, the necessary cost and life cycle assessment calculations have been performed as well. It was found that the cost of the PU-based healing agent is very reasonable while the extra costs of the capsules are for the moment still unacceptable. Environmental burdens associated with the PU precursor filled capsules are negligible (0.1-4.8%) in comparison with the impacts related to regular concrete repair to meet the design service life of 100 years.Concrete is the most manmade material solution produced and used worldwide. Its cornerstone is the cement composite due to the high emissions level and resources consumption volume. Roughly 5-7% of global carbon dioxide emissions come from cement manufacture process. The far-reaching alternative of replacement a clinker portion in the cement material composition has gained consensus. It becomes relevant in emerging economies since in the short-run there is not widely available ways for increasing the production capacity while diminish the environmental impact with no additional investment cost. Low carbon cement (LC3) is leading the contemporary paths towards facing environmental challenges and resource scarcity. This article aims at assessing the theoretical consideration of replacement of the Cuban traditional cements by LC3 according to housing case studies in Villa Clara province. On the basis of LCA background and the supply chain rationale, a procedure for discussing sustainable contribution of LC3 is designed and applied. Hollow blocks and mortars have been included in the calculations as well as the manufacturing/transportation processes for the entire supply chain of one semi-detached two-storey row houses built in the core of a slum-like settlement at Condado suburb-Santa Clara city. This approach demonstrates that the LC3 incorporation in the Cuban construction sector could afford considerable economic savings with the subsequent contribution in favour of the environment.Net zero energy is already an ambitious target for several buildings, especially since the DIRECTIVE 2010/31/EU that requires increasing the number of nearly zero energy buildings. The existing commercial building stock needs to be included in order to achieve the 2020 EU environmental targets. The main barriers of zero energy refurbishment of existing nonresidential buildings appear to be financial rather than technical, next to a number of other extrinsic factors that do not stimulate such an investment. While a business case for new zero energy buildings is believed to exist, controversial opinions can be found with respect to refurbishment of large buildings. The present study aims to identify the factors that affect the feasibility of the zero energy refurbishment of existing commercial buildings, while suggesting ways to create the business case addressing the Dutch market. Through interviews with real estate investors, the study identified the financial and technical barriers encountered today to undertake deep energy retrofit. Subsequently, the design interventions needed to refurbish a Dutch office building and meeting the net zero energy target were evaluated using a software complying with the Dutch standards NEN 7120. A risk and sensitivity analysis with Monte Carlo simulations showed the influence that design aspects, energy price and landlord-tenant agreements have on the business case. The study has concluded that a business case considering the energy savings alone is not sufficient to convince investors. However, when the design provides additional benefits, such as increasing the property value, the refurbishment can become feasible. This is an important observation to promote the refurbishment towards a zero energy building stock.Concrete is, after water, the most used material worldwide and its demand is projected to growth in the next 30 years. Among all concrete materials, cement presents the higher energy consumption and carbon emissions, thats why this industry has been developing several alternatives to gain sustainability. Reduction of clinker ratio by using Supplementary Cementicious Materials (SCM) allows a better use of existing capacities with low investment while a reduction in emissions, costs and energy per ton of cement is observed. The objective of this article is to assess the environmental and economic impact of a new cement with 50% of clinker: Low carbon cement (LC3). A procedure for evaluating sustainable and economic contribution of LC3, while projected demand is satisfied, is designed and applied in several scenarios. The results demonstrate that LC3 introduction is the best option to meet growing demand considering capital investment options in non-developed countries conditions with a reduction of ~30% in carbon emissions, of ~10% in costs and a faster return on investment related to OPC figures in Cuba.