Reliability and sensitivity of building performance simulation tools in simulating mechanically ventilated double skin façades

Abstract

The aim of the paper is to evaluate the performance and reliability of two whole-Building Energy Software (BES) tools in the simulation of narrow-cavity, mechanically ventilated double skin façade (DSF) envelopes. Two popular BES tools (EnergyPlus and IDA ICE) include a dedicated model for the simulation of window systems with a (forced) airflow in the cavity, and can, therefore, be used to simulate mechanically ventilated DSF systems. However, both these simulation approaches are based on the simplified estimation of the thermophysics of the ventilated cavity, and this may lead to inaccuracies in the prediction of the system's behaviour. Different configurations of mechanically ventilated, narrow-cavity, single-storey high DSFs are modelled with the two BES tools. Their ability to replicate i) the thermophysical behaviour of the systems and ii) the difference in the performance when one parameter in the DSF design is changed (i.e. glazing type and shading on/off) is assessed by means of comparison with experimental data available from test cell experiments. The sensitivity of the tools to (slightly) different configurations is a crucial feature for practitioners, who can use these tools to design DSFs and to take an informed decision on the detailed design of these systems (such as the glazing type and the activation/deactivation of the shading).