Due to the increasing usage of secondary fuels, which are relatively inhomogeneous, there are more fluctuations in the burning process. This leads to increased burden for the refractory and the kiln shellhot spots may occur. In order to reduce this burden, large cooling fans, which are blowing ambient air, are widely used.

 

Unfortunately this type of cooling shows some disadvantages:

•due to the low heat capacity of air a huge throughput is needed

•the consumption of electrical energy is high

•the cooling cannot be targeted specifically to a hot spot on a circumference

•fans emit a substantial amount of noise