Model Reduction of Radiative Heat Transfer by a Hierarchical Radiosity Method

Radiative heat transfer in buildings can be determined through the resolution of the radiosity equations. This technique requires the evaluation of geometric couplings between the elements of the scene called view factors. Obtaining them is particularly challenging, especially when obstructions are involved. In addition, the system to be solved can be cumbersome, since each surface is likely to interact with all the others and the number of nodes involved in the description of a complex scene is large. We present a solution method that refines the mesh of a scene while simultaneously constructing a representation at different scales of the view factors between the contributing elements, to avoid calculating all the transfers at the highest resolution. It thus considerably reduces the calculation time and makes the tool suitable with a routine use in a design perspective.