For the sheet of insulation specified in Problem 15.5, with a heat rate of 4 kW, evaluate the temperature at both surfaces if the cool side is exposed to air at 30°C with a surface coefficient of 28.4 W/m² · K.

Data From Problem 15.5

A sheet of insulating material, with thermal conductivity of 0.22 W/m · K, is 2 cm thick and has a surface area of 2.97 m². If 4 kW of heat are conducted through this sheet and the outer (cooler) surface temperature is measured at 55°C (328 K), what will be the temperature on the inner (hot) surface?