Chapter 2 Heat Conduction Equation2-131E The concrete slab roof of a house is subjected to specified temperature at the bottom surface and convection and radiation at the top surface. The temperature of the top surface of the roof and the rate of heat transfer are to be determined when steady operating conditions are reached. Assumptions 1Steady operating conditions are reached. 2 Heat transfer is one-dimensional since the roof area is large relative to its thickness, and the thermal conditions on both sides of the roof are uniform. 3Thermal properties are constant. 4 There is no heat generation in the wall. PropertiesThe thermal conductivity and emissivity are given to be k= 1.1 Btu/h⋅ft⋅°F and ε= 0.9. Analysis In steady operation, heat conduction through the roof must be equal to net heat transfer from the outer surface. Therefore, taking the outer surface temperature of the roofto be T2(in °F), ])460[()(4sky42221TTATThALTTkA−++−=−∞σεxT∞h ToLTsky
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