Paper Conference

Proceedings of eSim 2010: 6th Conference of IBPSA-Canada



Jon Hand, Aizaz Samuel

Abstract: As designers evolve facade details to reduce heat flows, features such as corners and junctions between building elements, are of increasing importance. Groups such as the PassivHaus Institute view thermal bridges and junctions in constructions as often exceeding the thermal impact of primary facade elements. This suggests more rigorous approaches in dynamic simulation may be of interest. Whole-building thermal simulation tools typically use 1D representations supplemented by linear thermal bridge coefficients. However, many advanced building sections are conceptually difficult to fit within a 1D heat flow regime. Those which offer 2D and 3D capabilities tend to be underutilized because of the resources required to attribute the additional dimensions of conduction. Existing 2D and 3D conduction analysis tools have difficulty scaling up to full scale buildings with environmental control schemes and usage patterns. Many also use steady state approaches which makes their predictions difficult to associated with dynamic whole-building tools. This paper explores methodologies for bridging the gap via better design of existing 1D models based on contributions from 2D and 3D tools as well as rules for translating complex building sections into model elements. It explores linear heat transfer coefficient representations of thermal bridges as well as hybrid models with a mix of 1D and 2D components.
Pages: 164 - 170