  A simplified model of indoor short wave radiation couplings adapted to
multi-zone simulations is proposed, thanks to a simplifying hypothesis and to
the introduction of an indoor short wave exchange matrix. The specific
properties of this matrix appear useful to quantify the thermal radiation
exchanges between the zones separated by windows or large openings. Integrated
in CODYRUN software, this module is detailed and compared to experimental
measurements carried out on a real scale tropical building.
