A concrete wall, which has a surface area of 20 m2 and is 0.30 m thick, separates conditioned room air from ambient air. The temperature of the inner surface of the wall is maintained at 25C, and the thermal conductivity of the concrete is 1 W/m*K.
(a) Determine the heat transfer rate through the wall for outer surface temperatures ranging from -15C to 38C, which correspond to winter and summer extremes, respectively. Display the results graphically.
(b) On your graph, also plot the heat transfer rate as a function of the outer surface temperature for wall materials having thermal conductivities of 0.75 and Explain the family of curves you have obtained.