This paper describes a new general method for building simulation programs which is intended to be used
for the modelling of complex facades. The term ‘complex facades’ is used to designate facades with venetian
blinds, prismatic layers, light re-directing surfaces, etc. In all these cases, the facade properties have a
complex angular dependence. In addition to this, such facades very often have non-airtight layers and/or
imperfect components (e.g. non-ideal sharp edges, non-flat surfaces, . . .). Therefore building planners
often had to neglect some of the innovative features and to use ‘work-arounds’ in order to approximate
the properties of complex facades in building simulation programs. A well-defined methodology for these
cases was missing. This paper presents such a general methodology.
The main advantage of the new method is that it only uses measureable quantities of the transparent
or translucent part of the facade as a whole. This is the main difference in comparison with state of the
art modelling based on the characteristics of the individual subcomponents, which is often impossible
due to non-existing heat- and/or light-transfer models within the complex facade.
It is shown that the new method can significantly increase the accuracy of heating/cooling loads and