How to find out rate of heat transfer through wall

 A furnace wall is built up with 100 mm thick refractory material and its area is 1 m2. Inner and outer temperature are 31 degree celcius and 10 degree celcius respectively. Thermal conductivity of the material is 0.05 W/ m.k.

Here,

Temperate difference dt = ( t2 - t1) = ( 10 - 31) 

Thickness, dx = 100 mm = 0.1 m

Thermal conductivity, k= 0.05 w/mk

We know, from Fourier law,

q = - k.dt/dx

= - 0.05*(10-31)/0.1

= 10.5 W/m2

Therfore, 10.5 W/m2 heat transfer through wall.