Conductive heat transfer through basement wall

AI Thread Summary
The discussion centers on calculating the time required for one dollar's worth of energy to be conducted through a concrete basement wall in an electrically heated home. The initial calculation used a thermal conductivity value of 1.7, but participants noted discrepancies with other sources suggesting a range of 0.1 to 1.7 for concrete. The formula for heat transfer, q=KAdeltaT/L, was applied, but the results indicated an unrealistic time of 1052 hours. Participants advised checking textbooks or data tables for accurate thermal conductivity values. Accurate values are crucial for obtaining a correct solution to the problem.
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Homework Statement



In an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 13.8oC. The temperature at the inside surface of the wall is 20.8oC. The wall is 0.118m thick and has an area of 9.43m2. Assume one kilowatt*hour of electrical energy costs $0.10. How many hours are required for one dollar's worth of energy to be conducted through the wall?

Homework Equations


q=KAdeltaT/L


The Attempt at a Solution

(1.7)*(9.43)*(20.8-13.8)/0.118=950.99 W $1=10000Whr
10000/950.99=1052 hrs...not working though?
 
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Where did you find your k value? And is it in the correct units?

-Mark

PS: You did mean to write 10.52 hrs I hope?
 
yes i mean to write that, I got 1.7 from online source, but someone else also used 1.5 but neither of those works?
 
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