Author Question: A slab of concrete and an insulating board are in thermal contact with each other. The temperatures ... (Read 332 times)

corkyiscool3328 · **on:** Jul 28, 2018

A slab of concrete and an insulating board are in thermal contact with each other. The temperatures of their outer surfaces are 68F and 50F. 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.
a. 9.7
b. 2.5
c. 5.3
d. 1.7
e. 28

Question 2

The R value of fiberglass batting, 3.5 inches thick, is 11 ft2/F/h/BTU. What is the thermal conductivity (in BTU/ft/F/s)?
a. 7.4 106
b. 2.7 102
c. 8.9 105
d. 1.4 104
e. 3.6 103