Question $1$

A Cupola furnace wall consist of the following. The first layer, face fire brick is $30cm$ thick with thermal conductivity of $0\mathrm{.}4\frac{W}{m}K.$ The second layer is a protective steel frame $4mm$ thick and thermal conductivity of $55\frac{W}{m}K.$ A third layer of $12cm$ insulation blanket of thermal conductivity of $0\mathrm{.}3\frac{W}{m}K.$ The inside temperature $($face temperature$)$ during the drying cycle was measured at $600C$ and outside temperature $80C.$

$1\mathrm{.}1$ Draw the multilayer furnace wall from the question. Also show the heat loss profile and heat resistance of each brick layer.

$(13)$

$1\mathrm{.}2$ Calculate the rate of heat loss $(Q$ in Watt$)$ through one wall of the furnace with a face surface area of $5m$ by $4m.$

$(20)$

$1\mathrm{.}3$ Convert your answer in $1\mathrm{.}2$ to kilowatt hour.

$1\mathrm{.}4$ Also calculate the interface temperature of layers $(T_3-T_4).$

$(4)$

$1\mathrm{.}5$ Explain the meaning of a small and a big thermal conductivity value $(\frac{W}{m}K)$ in relation to insulation.