Automatic Simplification of Complex Building Geometry for Whole-building Energy Simulations

The energy simulation of buildings with complex curved envelopes is still a difficult task. Although an accurate building representation is desirable for energy analysis, a refined mesh representation of (double)curved facades still requires a significant modeling effort for building energy simulation and in most cases the resulting models entail a simulation overhead that is incompatible with design times. This becomes more relevant in fully automated parametric and building energy optimization studies, where a computer program is responsible to instantiate several variations of a building energy model from parametric conceptual building masses. In such settings, it is mandatory that the generated simulation models are valid (i.e., without errors and with accurate building representation) and it is desirable that they are efficient (i.e., fast to run). To answer these challenges, this paper presents a computational tool that automatically simplifies the geometry of complex curved building envelopes for energy simulation. The tool is based on two heuristics - one that post-rationalizes building surfaces and another that samples large energy models and isolate and simulate their most representative parts. We tested our approach in two building masses with complex curved envelopes. The results show that the two heuristics, either combined or applied separately, are able to generate valid and fast building energy models with minimal impact on simulation output.