A thermopane window consists of two pieces of glass (k = 0.78 W/m/K) 7 mm thick that enclose an air space (k = 0.026 W/m/K 7 mm thick. The window separates room air at 20?C from the outside air at -10?C. The convection coefficient associated with the inner (room-side) surface is 10 W/m2?K, while that associated with the outer (ambient air) side is 80 W/m2?K. Assume that the air enclosed between the panes is stagnant and that radiation may be neglected.
What is the heat transfer through a window which is 0.8 m long by 0.5 m wide?