A model was developed to predict the decrease of the thermal performance of glass furnace regenerators due to fouling by flue gas condensates. The model consists of 4 parts: a) description of the thermal performance (heat transfer) of regenerator checkers; b) description of the heat transfer in the furnace combustion chamber; c) detn. of volatilization of S, Cl, and Na components from the melt; and d) modeling of chem. reactions in the deposition from flue gases in the regenerator. The aging and the redn. of the thermal efficiency due to fouling was predicted: for different checkerwork constructions or refractory types; as a function of pull rate; as a function of glass melt temps.; and as a function of applied cullet fraction. Depending on the different conditions, the predicted increase in energy consumption is .apprx.1 up to >3% per yr, mainly due to fouling. Cruciform and chimney block checkers seem to be less sensitive for this fouling than basketweave packings. As molten glass temps. increase, dust emissions and fouling rates are going up. According to the model calcns., a higher cullet fraction in the batch will lead to reduced aging rates of the regenerators. The model is in quite good agreement with practical observations in industrial furnaces. [on SciFinder (R)