• Energy Research

Abstract The building sector is well known as one of the significant contributors to climate change. The use of materials and energy are important drivers, both during construction and the whole life cycle. This study is part of a research to improve the Belgian national approach of life cycle environmental assessment for buildings. The current approach focusses mainly on material use, and the operational energy is estimated via the equivalent degree day method assuming a fixed value of 1200 equivalent heating degree days per year. This paper extends this widespread degree day approach to improve its accuracy by including the effect of various parameters (climate, building characteristics, obstructions by the environment, occupant behaviour). Step by step user-friendly input and graphical feedback is moreover considered necessary for designers and has been added. The annual heating energy estimated by our proposed semi-dynamic model has been validated by dynamic energy simulations using EnergyPlus of 8000 randomly generated cases. Both results have been plotted in a 2D graph. The slope of the linear regression through the origin is 0.8955, and the R-square value is 0.9058. Based on this comparison, it is concluded that the semi-dynamic model, with simplified input and fast results, has sufficient accuracy for the first design phases compared to the dynamic model.

Abstract 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.