(b) The inner and outer surfaces of a 25-cm-thick wall are at 27 SC and 45 C, respectively. The outer surface of the wall exchanges heat by radiation with surrounding surfaces at 40 C. and convection...

Extracted text: (b) The inner and outer surfaces of a 25-cm-thick wall are at 27 SC and 45 C, respectively. The outer surface of the wall exchanges heat by radiation with surrounding surfaces at 40 C. and convection with ambient air at 42 C with convection heat transfer coefficient of 9.0 W/m? K. Solar radiation incident on the surface is at a rate of 150 W/m?. If the emissivity and the solar absorptivity of the outer surface are 0.75 and 0.85, respectively: write the expression of the energy balance at the outer surface; (i) (ii) write the expression of conduction heat flux; (iii) calculate the convection heat flux; (iv) calculate the radiation heat flux, (v) calculate the effective thermal conductivity of the wall.