Comparison of Simulation Results for an Office Building Between Different BES Tools – The Challenge of Getting Rid of Modeller Influence and Identifying Reasons for Deviations

The model of the reference office building, reported in IEA SHC Task 56, is implemented by different experts in building simulations, with different tools (i.e. dynamics simulation tools such as EnergyPlus, TRNSYS, CarnotUIBK, ALMAbuild, DALEC, Modelica and quasi steady state calculation tool such as PHPP). The aim is to set up reference models for (virtually) testing different solar passive and solar active façade systems. Hence, identifying deviations between the resulting energy balance for heating and cooling of the used tools due to different levels of detail of their models is of great importance, while in the same time, trying to get rid of the user influence was experienced as a real challenge.
It can be concluded that even considering a relatively simple case study, it is hard to reach a good agreement between different tools and an additional calibration phase is necessary. In particular, it was found that the resolution of the window model can lead to considerable differences.
As a perspective, it seems to be a challenge if the building modelling is entrusted to non-expert users (e.g. from Building Information Modelling to Building Energy Modelling, where BIM-to-BEM interoperability issues might arise and affect the simulation results).