1. A composite wall is made of four different layers of materials (B, C, D & E) as shown. The overall height of the wall is 1.2 m (shown in figure), its length is 1.5 m and its total thickness is 36 cm (measured from B to E). Layer B (kB-=50 W/m.K) has a thickness of 10 cm, layers C and D are 6 cm thick with kc-45 W/m.K and kp-30 W/m.K. The thermal conductivity of the material in layer E is (KE) 15 W/m.K. The height of layer C is 40 cm and the height of layer D is 80 cm. The ambient air near layer B is at 250 C with a convection heat transfer coefficient of 75 W/m.K whereas the air at the free surface of layer E is at a temperature of 30 C with a corresponding convection heat transfer coefficient of 50 W/m.K. (Note: TBC-TBD & TCE-TDE). Neglect all contact resistances and radiative heat transfer. a) Draw a schematic diagram of the heat transfer problem configuration (show all relevant geometric, material, and thermodynamic parameters (symbols only) including the direction of heat transfer) b) Draw the appropriate thermal circuit for the heat transfer problem (this should correspond to your sketch in part a) above) c) Calculate the heat transfer rate (W) across the wall and across the individual layers d) Calculate the interface temperatures TBC and TDE and the free surface temperatures of layers B and E D E 1.2 m 111