Energy performance of fixed chimery kiln
The energy balance presented here is approximate, however, it gives an idea about the relative magnitude of the different components of
energy balance. The important losses to be considered are the surface and ground heat losses. When combined together they constitutes
to 34 % of the energy supplied. Monitoring of ground temperature below the kiln by TERI at a kiln near Calcutta revealed that the heat
penetrates up to 2.5 m below the floor of the kiln. Almost 300 tons of coal costing more than Rs 6 lakh is lost annually per kiln (kiln
capacity 30 lakh bricks per year), through surface and ground heat losses These losses can be reduced substantially by : a) using better
insulation –at least 6 inch ash layer on the top of the kiln and two layer soling at the kiln floor. b) by reducing the size of the kilns
(e.g. adopting zig-zag setting). In the existing kilns a fire travel rate of at least 8 m/day should be aimed against 5 m/ day which is achieved
at present. Increase in output helps because surface heat losses remains almost constant whether the output is high or low. c) to avoid
excessive ground heat loss, particular attention should be paid during site selection for the kiln, the kiln should be located on high ground
with good drainage, away from water bodies.
The total cost of construction of a new fixed chimney kiln based on improved designs is estimated to be around 8 -12 lakhs. In most of the
cases, it is possible to convert existing moving chimney kilns into improved fixed chimney kilns. During conversion, part of the trench can
be used as it is. Also bricks recovered from the demolition of old kiln can be used for the construction of the new kiln, these measures
reduces the cost of the new kiln.