A realistic radiative heat transfer model for building energy simulation programs

A neural network based model for interior longwave radiative heat transfer has been developed and implemented into a new computer code, BERHT (Building Energy with Radiative Heat Transfer). The model accounts for the non-gray effect of absorping species (CO2, H2O, and small particulates) in a building environment and the geometric effect of a three-dimensional building structure. Two numerical studies have been carried out on a 60m2rectangular single story building. Numerical data are generated. For nominal concentration of CO2, H2O, and small particulates, results show that the presence of an absorbing/emitting medium has important effects on the distribution of the total heat transfer between convection and radiation. The presence of a participating medium, however, has only a minimal effect on the overall heat transfer and the temperature of the encloused air. It is shown that the overall energy balance is strongly influenced by external parameters. The "greenhouse" effect is simulated numerically. Results confirm that the absorption of short-wave radiation by surfaces and the subsequent heat transfer from the surfaces to the air mixture in the room is the primary mechanism for the greenhouse effect.