Automatic generation of as-is BEM models of buildings

Abstract

This paper shows a method with which to create a proprietary as-is 3D semantic thermal model of a building and transform it into standard BEM formats. Geometric and relational information regarding the essential structural elements of the building (i.e., zone, ceiling, floor, wall, door, etc.) is, together with their corresponding as-is temperatures, first extracted from thermal points clouds of the scene and then adapted to the standard geometric BEM requirements. Non-geometric properties concerning definitions and properties of envelopes, windows and doors are also defined as essential information. After all this information has been collected, a BEM file is eventually generated in order to be used in energy simulation software. One of the specific features of this work is the generation of as-is BIM formats of the interior of a building that are later adapted for energy simulation applications in EnergyPlus and TRNSYS software. An ASCII file containing the temperatures of the main structural elements of the building is also created. The method has been tested on real thermal point clouds of the ground floor of a building, yielding promising results.