Details the development of algorithms for modelling the interreflected solar heat gain from neighbouring structures (secondary solar heat gain) and implementation of the algorithms in a building energy simulation program. States the algorithms account for the contribution from unobstructed and interreflected solar radiation on the solar heat gain through opaque and transparent surfaces. The algorithms are based on the ray-tracing program Radiance.

KEYWORDS: year 1995, Algorithms, computer programs, solar heat gain