1 INVOCATION OF BUILDING SIMULATION TOOLS IN BUILDING DESIGN PRACTICE Pieter de Wilde (1), Godfried Augenbroe (2) and Marinus van der Voorden (1) (1) Delft University of Technology, Faculty of Architecture, Building Physics Group Delft, 2600GA, The Netherlands (2) Georgia Institute of Technology, College of Architecture, Doctoral Program Atlanta, GA 30332-0155, USA ABSTRACT This paper reports on two case studies that explore the current use of computational tools in building design scenarios. Goal of the project is to gain insight into the role of tools in the design process and to investigate and capture the designer’s viewpoint concerning building simulation. This viewpoint is essential for a successful application of simulation in the design process, but might differ from the viewpoint of the developer of simulation tools. Context of these case studies is an ongoing Ph.D.- project at Delft University of Technology that focuses on better integration of analysis tools (simulation tools in particular) in informed design strategies. KEYWORDS Building design practice, energy saving components, building simulation, case studies, process modeling INTRODUCTION Due to development and use of novel design features and due to increasing emphasis on performance aspects like energy consumption and (thermal) comfort, the need for adequate decision support during the design process is ever growing. Design decisions concerning specific parameters like U- value, airtight-ness and thermal capacity are known to have a strong impact on mentioned performance aspects. Because of the complex interaction between these design decisions and mentioned performance aspects one would expect these decisions to be based on rigorous design analysis, e.g. supported by building simulation tools. In building research, the use of computational tools for building performance simulation is widely accepted. However, in spite of clear merits and successful demonstration projects like the IEA Task 13 low energy dwellings [1], application of these tools by building design teams has not become common accepted practice. Many research projects have aimed at bridging the gap between the world of building design and the world of building simulation, so far however without overwhelming success. Although a number of plausible causes has been found (e.g. the unavailability of appropriate models, the costs of simulation or the knowledge required to use expert tools) it has been proven to be hard to provide real solutions, hence the same problems prevail. Development of a strategy for the use of simulation tools as an indispensable support instrument in building design is the goal of this research [2]. This strategy will be defined by a set of causal relationships between qualified design requests and deployment of pre-defined ‘design evaluation experiments’. The term ‘experiment’ is used here in its broadest meaning. Any procedure that can be used to test the performance of a given design , be it through physical experimentation, virtual experimentation through simulation or thought experiments (engineering judgement) would qualify as a ‘design evaluation experiment’ in this context. In the case of simulation based experimentation, it is assumed that each experiment can be associated with an accredited set of simulation tools. Simulation runs are followed by dedicated, request specific post processing of the simulation output results. This post processing transforms the raw output data to semantic performance results in the context of the design request. In the current stage of the research, the broad field of building design is narrowed down to a specific design domain where the role of simulation is of particular importance: the integration of energy saving components in existing building concepts. Energy saving components can be defined as integrated building components that are designed to contribute to lower energy demands. Examples of energy saving components are sun spaces, solar walls, advanced glazing systems or photo-voltaic arrays. This paper focuses on a structured analysis of two real building design cases (real life building design scenarios) that involve the use of simulation tools.