The radiant external environment may be described by two hemispheres, above and below the horizontal plane, which are discretised into patches of known solid angle. Occlusions to these patches may be combined and represented as some patch fraction for which the radiant characteristics are defined by the dominant occlusion. By solving for radiant exchanges between each surface in a scene and its associated (un)occluded patches, we have a simplified radiosity algorithm (SRA). This paper describes the application of t his SRA to solve for predictions of (i) solar radiation, (ii) interiordaylight and (iii) longwave radiation. Comparisons with a ray tracing program show that accurate results are achieved at a computational cost several orders of magnitude lower.