Paper Conference

Proceedings of BauSim Conference 2008: 2nd Conference of IBPSA-Germany and Austria


TRNSYS 17: Das 3D-Strahlungsmodell

Johannes Aschaber, Marion Hiller, Robert Weber

Abstract: Evaluating innovative building energy concepts may make detailed modeling of 3-dimensional energy transport by radiation within the building necessary. The upcoming version 17 of the dynamic simulation package TRNSYS meets these demands with a new radiation model integrated into the multizone building model. This paper briefly describes the new geometrical model for long-wave and short-wave radiation handling within a thermal zone. The new radiation model applies the so-called Gebhart factors which are based on view factors. The long-wave and short-wave diffuse radiation exchange between all surfaces of an enclosure are calculated explicitly including all possible paths. Point sources are treated similarly. In addition, external shading factors of solar radiation can be handled automatically and the incoming beam radiation is distributed depending on the sun’s position, the external shading and the geometry of the thermal zone. For convenient geometry input and visualization a graphical interface will be available for TRNSYS 17. From the resulting geometric information the required inputs such as view factors, shading factors and distribution factors are calculated in a preprocessing step.
Pages: 2 - 4