For the composite wall of a house, shown in Figure P13-10, determine the temperatures at the inner and outer surfaces and at the interfaces. The wall is composed of 2.5 cm thick plaster wall (k = 0.20 W/m-oC) on the inside, a 9 cm thick layer of fiberglass insulation (k = 0.038 W/m-oC), and a 1.25 cm plywood layer (k = 0.12 W/m-oC) on the outside. Assume the inside room air is 20 oC with convection coefficient of 10 W/m2 -oC and the outside air at -20 oC with convection coefficient of 20 W/m2 -oC. Also, determine the rate of heat transfer through the wall in Watts. Assume one-dimensional heat flow through the wall thickness.
Figure P13-10

Transcribed Image Text:

Fiberglass Plaster wall insulation Plywood Inside Outside 2.5 cm - |-9 cm –125 cm - 9 -1.25 cm