Energy performance assessment of an existing double-skin façade: measurements and simulation

An existing office building with an active double skin façade in Luxembourg has been
analyzed. In the first step in-situ measurements have been performed. For this
purpose outside, inside and cavity conditions have been measured for representative
summer and winter conditions. In a second step, a thermal simulation using TRNSYS
was performed. The simulation model has been compared to the time limited series of
measurements and thus has been validated for some of the annual meteorological
conditions. Then the model has been extrapolated to a whole year in order to assess
the energy performance of the given façade. Further a parametric study of alternative
façades has been carried out based on the validated simulation model to assess their
own performances. For the given case study building, the double skin concept
energetically performs well compared to other concepts with non outside (non weather
exposed) solar protection, but worse than an external solar protection.
The thermal comfort level in the rooms has also been determined by simulation - the
calculated room averaged comfort level is quite optimal, but further investigations
regarding the local comfort close to the glazed façades still have to be achieved.