Validation of a hygrothermal whole building simulation software

One trend in whole building simulation is the incorporation of hygric interaction of room and enclosure. This allows besides a more detailed comfort assessment the optimization of building components to avoid moisture related damage or failure. Still, the main interest in the building design and optimization phase is the energy use combined with the occupants comfort. Several existing standards and guidelines allow the validation of building energy simulation tools, like ASHRAE 140 (ANSI/ASHRAE 140-2007 2007) or VDI 6020 (VDI Richtline 6020 2001). A newly developed hygrothermal whole building model will be compared to the validation cases of these two standards. In addition, the validation of the hygric part of the simulation tool will be shown by comparing with an experimental set-up. These evaluations allow on one hand a critical discussion about the usability of the standards for evaluation of building energy software. We found problems with the description of the boundary conditions, especially in VDI 6020. On the other hand, the usability of the new software for energy and comfort assessment is shown by a good agreement with both standards. Furthermore, we suggest new validation experiments to provide not only thermal, but also comfort and hygrothermal comparison cases.