An insulated frame wall of a house has an average thermal

Chapter 2, Problem 2.51

(choose chapter or problem)

An insulated frame wall of a house has an average thermal conductivity of \(0.04 \mathrm{Btu} / \mathrm{h} \cdot \mathrm{ft} \cdot{ }^{\circ} \mathrm{R}\). The thickness of the wall is 6 in. The inside air temperature is \(70^{\circ} \mathrm{F}\), and the heat transfer coefficient for convection between the inside air and the wall is \(2 \mathrm{Btu} / \mathrm{h} \cdot \mathrm{ft}^{2} \cdot{ }^{\circ} \mathrm{R}\). On the outside,the ambient air temperature is \(32^{\circ} \mathrm{F}\) and the heat transfer coefficient for convection between the wall and the outside air is  \(5 \mathrm{Btu} / \mathrm{h} \cdot \mathrm{ft} \cdot{ }^{\circ} \mathrm{R}\). Determine at steady state the rate of heat transfer through the wall, in \(\text { Btu/h per } \mathrm{ft}^{2}\) of surface area.