A comprehensive building model for performance-guided decision support
This paper reports on a specific effort within the ongoing research and development project SEMERGY. This project is geared toward the development of a performance-guided decision making environment for building design and retrofit. A multi-objective optimization environment requires a dynamic representation of the building, which includes all necessary data for the underlying calculation engines (e.g., energy demand calculation, cost estimation, Life Cycle Analysis). This paper explores the capacities and deficiencies of some existing building data models (IFC and GBXML), within the context of SEMERGY project and reports on the development of „SEMERGY Building Model“ (SBM). SBM is a comprehensive building representation, tailored to meet the requirements of advanced energy simulation procedures and normative calculation routines for common inquiries. It can be extended for further functionalities with minimal effort, enables efficient optimization iterations and allows for data entry simplification to reduce user effort and error.
From N. Ghiassi, F Shayeganfar, U. Pont, A. Mahdavi, J. Heurix, S. Fenz, A. Anjomshoaa, A. Tjoa: „A comprehensive building model for performance-guided decision support„;
in:“Proceedings of the 2nd Central European Symposium on Building Physics 9-11 September 2013, Vienna, Austria„, A. Mahdavi, B. Martens (Hrg.);ÖKK-Editions, 1 (2013), ISBN: 978-3-85437-321-6; S. 35 – 42.
„Despite the advances in the development of building performance assessment tools over the past decades, the uptake of such tools within the design community has been relatively slow. Their integration in the design process is limited to the late stages, mainly to analyze the final design solution for certification purposes (Hensen et al. 2004). Little attention has been paid to their potential to support the generation of design alternatives, to make informed choices between different design options, or to optimize building and/or systems (De Wilde 2004). There is evidence that decisions taken during conceptual design have a disproportionate impact on the final building energy performance (Domeshek et al. 1994) and that the cost, time, and effort needed for implementing changes early in the design process are substantially lower (McGraw Hill 2007). Nonetheless, assessment tools are rarely used to support early design phase tasks such as feasibility studies and conceptual design evaluations. The low application of performance assessment tools has been in part attributed to low market interests and high time-cost of applying them. On the other hand, studies show that the number of tools developed in the past decade to address specific needs and preferences of architects, who are the main decision makers in the early design stages, is very limited compared to those developed for experts in the field of building physics (Attia 2011). Architects‘ main criteria for selection of a performance assessment tool are usability and intelligence of the software (Attia 2011). In other words, they seek an easy-to-use application, which can interpret calculation results and draw comprehensible conclusions. SEMERGY (Mahdavi et al. 2012a, 2012b, Pont et al. 2013), represents an attempt towards development of a performance guided building optimization environment. Its aim is to overcome usability issues of available tools for designers and novice users by simplifying the accumulation and entry of data for assessment purposes, as well as to ameliorate system intelligence to analyze assessment results and propose clear design solutions. The SEMERGY environment is intended to support users in selection of appropriate building products and construction materials from the large variety of products available on the market, in order to achieve the best energy and environmental performance possible within the limits of the user’s financial means. It targets three different user groups: i) Novice users with little or no knowledge of the building sector, ii) Architects and building designers who demand a highly flexible and rapidly adaptable environment capable of generating adequate responses to problems in the planning process, iii) Municipalities, developers, and other authorities, interested in a toolbox for fast evaluation of buildings at a larger scale. According to the expertise of the user, the initial design intentions, as well as desired performance level and available funds, are communicated to SEMERGY through a web-based Graphical User Interface (novice users), extracted automatically from an advanced building information model (CAD, BIM), or derived from GIS data (Mahdavi et al. 2012a).“
„Keeping the geometry unaltered, SEMERGY automatically identifies various legitimate design alternatives with regard to material combinations and construction configurations. Through optimization iterations, optimal solutions for all various building components are selected and suggested to the user. SEMERGY uses different computational engines to evaluate the proposed design in view of multiple criteria of investment costs, energy demand and environmental impact. It currently incorporates both simple normative procedures (steady-state monthly and annual calculation methods based on standards and guide-lines) (e.g. Austrian Standards Institute 2009, OIB 2007) and advanced simulation engines (e.g. Energy Plus 2013) to arrive at the value of the pertinent performance indicators. The functionalities of SEMERGY will be further extended by integration of other calculation procedures such as life cycle analysis and cost estimation. To reduce user effort, SEMERGY explores the potential of the semantic web technologies (Berners- Lee et al. 2001, Shayeganfar et al. 2008) towards populating the input data for calculation purposes via the navigation of the extensive but currently ill- structured web-based information space pertaining to building materials, elements, components, and systems, as well as microclimatic, financial and legal information. Such information is extracted from the web and restructured into ontologies of semantic data, which facilitate queries and imposition of rule based logics to help automatically retrieve relevant information for computation purposes. In-depth description of the optimization procedure and the incorporated semantic technology can be found in Shayeganfar et al. 2013, and Heurix et al. 2013. To enable the transfer of data between different components of the SEMERGY environment (User Interface, computational engines, semantic interface), building related information is structured in the form of a building data model, which includes all required data for different calculation engines integrated in SEMERGY. Appropriate data is then selected from this base model and dispatched to various calculation engines for evaluation purposes. The present paper explores various features an appropriate data representation in the context of the SEMERGY environment, points out some of the short-comings of standard building representations (Industry Foundation Classes and Green Building XML) for the purpose of this project, and reports on the development of the SEMERGY Building Model (a.k.a. SBM).“