Chapter 3, Problem 69P

A 12-m-long and 5-m-high wall is constructed of two layers of 1 -cm-thick sheetrock $(k=0.17\text{ W/m}\text{.K})$ and spaced 16 cm by wood studs $(k=0.11\text{ W/m}\text{.K})$ and whose cross section is $\text{16 cm }\times \text{ 5 cm}$. The studs are placed vertically 60 cm apart, and the space between them is filled with fiberglass insulation $(k=0.034\text{ W/m}\text{.K}).$ and The house is maintained at 20°C and the ambient temperature outside is -9°C. Taking the heat transfer coefficients at the inner and outer surfaces of the house to be 8.3 and 34 W/m² -K, respectively, determine (a) the thermal resistance of the wall considering a representative section of it and (b) the rate of heat transfer through the wall.