Chapter 1, Problem 1.3P

A concrete wall, which has a surface area of $20{\text{m}}^{\text{2}}$ 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 $25°\text{C,}$ and the thermal conductivity of the concrete is $1\text{W/m}\cdot \text{K}\text{.}$

1. Determine the heat loss through the wall for outer surface temperatures ranging from $-15°\text{C}$ to $38°\text{C,}$ which correspond to winter and summer extremes, respectively. Display your results graphically.
2. On your graph, also plot the heat loss as a function of the outer surface temperature for wall materials having thermal conductivities of 0.75 and $1.25\text{W/m}\cdot \text{K}\text{.}$ Explain the family of curves you have obtained.