Abstract This thesis investigates the heat transfer mechanisms within a fast-firing tunnelkiln, a critical component in the brick manufacturing process. Tunnel kilns, widely used in the ceramics industry for the production of coarse ceramics such as bricks, operate through a continuous process where kiln cars transport goods through distinct zones. In order to reduce the CO2 emitted by the brick burning process the heat transfer inside the kiln has to be improved. The efficiencies of the heat transfer within these zones are crucial for the overall energy consumption and the quality of the final product. Thus, a series of CFD simulations with different models and setups are carried out in order to answer the question if it is advantageous to lower the ceiling inside the given fast firing brick kiln. As can be seen, the placement of the bricks inside the kiln has a significant impact on the heat transfer and can be altered more easily than changing the geometry of the kiln itself. Lowering the ceiling inside the kiln would involve expensive modifications compared to changing the mount of the bricks on the kiln cars. The results of the simulations are also validated with provided experimental data collected by measurement of different brick and air temperatures. Different placement of bricks in the generated models can be used as a starting point for future investigations to further increase the efficiency.