SIGNIFICANCE OF EXCHANGE AREA ADJUSTMENT IN ZONE MODELING

Direct exchange areas, a basic ingredient of the zone method, must obey certain constraints, which represent conservation of radiant energy. This is, however, never possible in practice because of errors in the estimation and usage of the areas. Recently, Larsen and Howell suggested an optimization procedure for adjusting these areas to conform to the constraints. This procedure is applied, in the present work, to two practical problems for evaluating the significance of the area adjustment in the modelling of thermal radiation using the zone method. The study reveals that the type of weighting factor selected in the method of Lagrange multipliers used by Larsen and Howell for adjustment of the areas is immaterial since the smoothing itself is found to have no appreciable effect on the zone method predictions.