  As part of our efforts to complete the software CODYRUN validation, we chose
as test building a block of flats constructed in Reunion Island, which has a
humid tropical climate. The sensitivity analysis allowed us to study the
effects of both diffuse and direct solar radiation on our model of this
building. With regard to the choice and location of sensors, this stage of the
study also led us to measure the solar radiation falling on the windows. The
comparison of measured and predicted radiation clearly showed that our
predictions over-estimated the incoming solar radiation, and we were able to
trace the problem to the algorithm which calculates diffuse solar radiation. By
calculating view factors between the windows and the associated shading
devices, changes to the original program allowed us to improve the predictions,
and so this article shows the importance of sensitivity analysis in this area
of research.
