A factory has a sheet metal wall with a thermal conductivity of 105 Btu/h-ft-oF. The wall thickness is 1 inch. (a) If the inside temperature of the wall is 80.0oF and the outside temperature of the wall is 10.0°F, determine the heat transfer rate per unit area from conduction (the conductive heat flux) for the wall. (b) For an inside wall temperature of 80.0°F, plot the conductive heat flux through the wall for outside wall temperatures ranging from 90.0°F to 0.0°F. (c) For an outside wall temperature of 10.0°F, plot the conductive heat flux for inside wall temperatures ranging from 50.0°F to 85.0°F. Discuss how this relates to gaining cost savings by heating a building to a lower temperature in the winter.

Given: ? = 105 Btu/h-ft-°F; ?x = 1 in = 0.0833 ft

What will be an ideal response?


(a) To = 10.0°F, Ti = 80.0°F

Qcond = - ?A dT/dx



For the wall, approximate: dT/dx = T1-T0/?x = 840.3 °F/ft



Qcond/A = -(105 Btu/hr-ft-°F) (840.3 °F/ft) = -88,200 Btu/hr-ft2



b)



c)

Trades & Technology

You might also like to view...

____________________ are semi-feral dogs that live in close approximation to towns where they survive by scavenging on garbage

Fill in the blank(s) with correct word

Trades & Technology

Technician A says to always use new gaskets when transferring oil pans and valve covers from an old engine to a reman engine. Technician B says it is acceptable to reuse gaskets that are in good condition. Who is correct?

A. Technician A B. Technician B C. Both A and B D. Neither A nor B

Trades & Technology

As the number of companion animals continues to grow, the range and variety of petfoods continue to expand

A. True B. False

Trades & Technology

Find dimensions B in centimeters to one decimal place.

Fill in the blank(s) with the appropriate word(s).

Trades & Technology