A slab of concrete and an insulating board are in thermal contact with each other. The temperatures of their outer surfaces are 68°F and 50°F. Determine the rate of heat transfer (in BTU/ft2⋅h) if the R values are 1.93 and 8.7 ft2⋅°F⋅h/BTU, respectively.

Question

Quizplus · Accepted Answer

The rate of heat transfer can be calculated using the formula: Q = ΔT / (R1 + R2). Here, ΔT = 68°F - 50°F = 18°F, R1 = 1.93, and R2 = 8.7. Thus, Q = 18 / (1.93 + 8.7) = 1.7 BTU/ft²⋅h.

A Slab of Concrete and an Insulating Board Are in Thermal