Batch melting is an integral phenomenon to be considered in the simulation of a glass furnace and it is important to account for radiative and convective heating on top by the combustion gases and convective heat transfer from the glass melt below the batch. The batch model accounts for heat conduction within the batch and the batch velocity is not assumed constant within the tank, but rather it is explicitly calculated. A species transport equation is solved to account for the batch melting, the rate of which could be either thermally or kinetically controlled.

The energy equation includes an additional sink term resulting from the endothermic conversion of batch to glass melt. This is a very general 3D model which can be applied to a wide variety of furnaces (end-fired, side-fired etc.) without any ad-hoc modifications. The presence of cullet in the batch can also be taken into account through an additional heat sink term.