Chapter 2, Problem 2.19P

Consider a $300\text{mm}\text{×}\text{300}\text{mm}$ window in an aircraft. For a temperature difference of $80°\text{C}$ from the inner to the outer surface of the window, calculate the heat loss through $L=10\text{-mm-}$ thick polycarbonate, soda lime glass, and aerogel windows, respectively. The thermal conductivities of the aerogel and polycarbonate are $k_{\text{ag}}=0.014\text{W/m}\cdot \text{K}$ and $k_{\text{pc}}=0.21\text{W/m}\cdot \text{K,}$ respectively. Evaluate the thermal conductivity of the soda lime glass at 300 K. If the aircraft has 130 windows and the cost to heat the cabin air is $\$1\text{/kW}\cdot \text{h,}$ compare the costs associated with the heat loss through the windows for an 8-hour intercontinental flight.