Question

Homes are often insulated with fiberglass insulation in their walls and ceiling.The thermal conductivity of fiber glass is 0.040W/m⋅K. Suppose that the total surface area of the walls and roof of a windowless house is 370m2 and that the thickness of the insulation is 10 cm. At what rate does heat leave the house on a day when the outside temperature is 30∘C colder than the inside temperature?

Answer 1

Answer:

4440 W

Explanation:

k = Heat conduction coefficient = 0.04 W/(m·°C)

A = Area = 370 m²

l = Thickness = 10 cm

$\Delta T$ = Difference in temperature = 30°C

Rate of heat transfer is given by

$Q=\dfrac{kA(T_2-T_1)}{l}\\\Rightarrow Q=\dfrac{0.04\times 370\times 30}{10\times 10^{-2}}\\\Rightarrow Q=4440\ W$

The rate of energy transfer is 4440 W