Question

A flat furnace wall is constructed of a 4.5 in (114 mm) layer of Silo-cel brick, with a thermal conductivity of 0.08 Btu/ft·h·˚F (0.138 W/m·˚C), backed by a 9-in. (229-mm) layer of common brick, of conductivity 0.8 Btu/ft·h·˚F(1.38 W/m.˚C). The temperature of the inner face of the wall is 1400˚F (760˚C), and that of the outer face is 170˚F(76.6˚C).

(a) What is the heat loss through the wall?

(b) What is the temperature of the interface between the refractory brick and the common brick?

(c) Supposing that the contact between the two brick layers is poor and that a “contact resistance” of 0.50˚F·ft2.h/Btu (0.088˚Cm2/W) is present, what would be the heat loss?

Answer 1