An electric kitchen range has a total wall area of 1.40 m2 and is insulated with a layer of fiberglass 4.00 cm thick. The inside surface of the fiberglass has a temperature of 175o C, and its outside surface is at 35.0o C. The fiberglass has a thermal conductivity of 0.040 W/.m ? K. (a) What is the heat current through the insulation, assuming it may be treated as a flat slab with an area of 1.40 m2? (b) What electric-power input to the heating element is required to maintain this temperature?
Solution 66E Step 1 of 4: The pictorial representation of given problem, Step 2 of 4: (a) What is the heat current through the insulation, assuming it may be treated as a flat slab with an area of 1.40 m2 Given data, Length of fiberglass, L = 4 cm=0.04 m Conductivity of fiberglass, k = 0.040 W/m.k Area of the fiberglass slab, a = 1.4 m 2 Outside temperature,T = 35 c=308 K o 0 inside temperature,T = i75 c=448 K To find, Heat current , H=