In: Physics
In laboratory tests, a new construction material was found to conduct heat at a rate of 10.2 Btu’s per hour per square meter of surface area. The temperature on one side of the wall was held at a constant 5 F while the other side was held at 70 F. The test specimen was 12.0 inches thick. What is the ambient air temperature (F) on the warm side of the wall? Assume there is free convection on the warm side of the wall, and the warm side is indoors.
conductivity = 10.2 Btu / hr = 2.99 W / mK3
thickness = 12 x 5 / 2 cm
= 30 cm
= 0.3 m
area = 1 sq m
C / 100 = F - 32 / 180
5F = -15 C , 70F = 21 C
The ambient air temperature = Q = conductivity x Area ( T inside - T outside ) / thickness
= 2.99 x 1 sq .m [ 21 - ( - 15 ) ] / 0.3
= 2.99 x [ 21 + 15 ] / 0.3
= 358.80 J
Q = T = 358.80 C = 649.04 F