1. The problem statement, all variables and given/known data The cross section of a 20 cm thick, 3 m wide, and 1 m high composite wall is shown. The conductivities of materials A, B and C are 1.0, 0.1, and 0.05 W m-1 K-1, respectively. One side is exposed to air at 295 K with a heat transfer coefficient of 4 W m-2 K-1, and the other side is exposed to air at 260 K with a heat transfer coefficient of 16 W m-2 K-1. Estimate the heat flow through the wall. Carefully discuss any assumptions you make. 2. Relevant equations 3. The attempt at a solution For this problem, my biggest concern is if I did my thermal circuit correctly. Also, is the area just the area of each composite material perpendicular to the direction of heat flow? The reason I got 5 sections of A,B, and C is because the width is given as 3 meters, and a divide by 40+20 = 60 cm to get 5 sections, so there is a lot of parallel heat flow happening here.