Heat Transfer (Conduction) problem

[toddler]

Homework Statement

Find the amount of thermal energy that flows per day through a solid oak wall 10.0 cm thick, 3.00 m long, and 2.44 m high, if the temp of the inside wall is 21.1 C while the temp of the outside wall is -6.67 C.

Homework Equations

Q= k(A)(T2-T1)t/d

coefficient of thermal conductivity for the oak is 1.47 x 10^-1

The Attempt at a Solution

This is a review question in my textbook and it shows:

=

(0.147 J/m s C) (24.0 m squared) (21.1 C - (-6.67 C))(24 hr)(3600 s/1 hr)
_______________________________________________________________
(0.100 m)




I understand the problem and the application, I am just unsure of how to get the area, A, for these problems. ...how did the 24 m^2 come about?

 

[AlephZero]

Hmm... the question says the area is 3.00 * 2.44 = 7.32 m^2.

I think the "24 m^2" is a typo.

 

[m2003]

The 24 m^2 comes from the surface area of the oak wall. To calculate the surface area, you need to find the area of each side of the wall and then add them together. In this case, the wall is 10.0 cm thick, 3.00 m long, and 2.44 m high, so the surface area would be 2(3.00 m x 2.44 m) + 2(10.0 cm x 2.44 m) + 2(10.0 cm x 3.00 m) = 24.00 m^2. This is the total surface area of the wall, which is needed for the equation Q= k(A)(T2-T1)t/d. I hope this helps clarify the solution for you.