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Question 3.299E: The sun shines on a 1500 ft^2 road surface so it is at 115 F...

The sun shines on a 1500 ft ^{2} road surface so it is at 115 F. Below the 2 inch thick asphalt, average conductivity of 0.035 Btu/h-ft-F, is a layer of compacted rubbles at a temperature of 60 F. Find the rate of heat transfer to the rubbles.

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\dot{ Q }= k A \frac{\Delta T }{\Delta x }

 

=0.035 \frac{ Btu }{ h – ft – R } \times 1500 ft ^{2} \times \frac{115-60}{2 / 12} \frac{ R }{ ft }

 

= 17325 Βtu/h

 

 

1

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