Consider the attic of a home located in a hot climate. The floor of the attic is characterized by a width of \(L_{1}=8 \mathrm{~m}\) while the roof makes an angle of \(\theta=30^{\circ}\) from the horizontal direction, as shown in the schematic. The homeowner wishes to reduce the heat load to the home by adhering bright aluminum foil \(\left(\varepsilon_{f}=0.07\right)\) onto the surfaces of the attic space. Prior to installation of the foil, the surfaces are of emissivity \(\varepsilon_{o}=0.90\).

(a) Consider installation on the bottom of the attic roof only. Determine the ratio of the radiation heat transfer after to before the installation of the foil.

(b) Determine the ratio of the radiation heat transfer after to before installation if the foil is installed only on the top of the attic floor.

(c) Determine the ratio of the radiation heat transfer if the foil is installed on both the roof bottom and the floor top.

Transcribed Image Text:

A, 1, 7 Attic A2, E2T 0-30 4 = 8 m +