The inside wall of a furnace needs to be designed such that it transmits a
maximum heat flux of 600 W/m2
. The inside wall temperature will be 1100°C and the
outside temperature will be 150°C. We have two different types of bricks from which we
can make the wall:
Type 1: 24 x 12 x 8 cm, k = 0.7 W/m·K, maximum allowable temperature = 850°C
Type 2: 24 x 12 x 8 cm, k = 1.6 W/m·K, maximum allowable temperature = 2200°C
If the two bricks cost the same amount of money, what is the most economical design for
the brick wall?
The bricks can be oriented in any direction and as many bricks as necessary can be used.
Assume perfect heat transfer between adjacent bricks.