Coupling CAD tools and building simulation evaluators

The ISE (Intelligent Simulation Environment) concept, developed by CSTB since the early nineties, has been applied to the development of various Simulation Environments (such as IISiBat III for TRNSYS or IISiBat II for COMIS). This concept has also been used to develop a prototype which aims at helping researchers to document their models and to store them in a neutral way, within structured model libraries [1]. The Simulation Environments developed are very often seen by the users as “only” userfriendly interfaces, whereas they are more than that. Whatever, the schema-blocks front-ends are appreciated and widely used worldwide (there are more than 300 institutes and consulting companies, worldwide, which are equipped with the latest version of TRNSYS). Nevertheless this kind of front-end (schemablocks) is still too much abstract, too much technical for users such as architects which are more used to work with CAD tools. Coupling CAD tools and Simulation Environments such as IISiBat represents a significant improvement both for the userfriendliness and for the efficiency of use. Geometrical data can be automatically reexploited (less errors due to re-keying), additional geometrical data, such as HVAC system pattern, can be added through the CAD tool. At this time most of the CAD tools can export DXF files. At the international level, the IAI (International Alliance for Interoperability) is leading the development of the IFC (Industry Foundation Classes) which are expected to replace soon the current DXF files (allowing to store more “semantic” within the files). After introducing briefly the ISE concept, this paper focuses on the coupling between CAD tools and Building Simulation Evaluators (such as TRNSYS). The prototype of a tool called “SimCAD” is described. This tool enables the users to read DXF or IFC files, to add information and to translate the geometrical information into the data usable by the targeted Simulation Environment.