A certain building wall consists of 6 0 in of concrete k 1 2 W m C , 2 0 in of fiberglass insulation, and 38 in of gypsum board k 0 05 W m C The inside and outside convection coefficients are 2 0 and 7 0 Btu h ft2 F, respectively The outside air temperature is 20F, and the inside temperature is 72F...

m 5710 2255106 253210 kgsec 912 kg ...

A certain building wall consists of 6.0 in of concrete [k = 1.2 W/m C], 2.0

Question:

A certain building wall consists of 6.0 in of concrete [k = 1.2 W/m ∙ ºC], 2.0 in of fiberglass insulation, and 38 in of gypsum board [k = 0.05 W/m ∙ ºC]. The inside and outside convection coefficients are 2.0 and 7.0 Btu/h ∙ ft2 ∙ ºF, respectively. The outside air temperature is 20ºF, and the inside temperature is 72ºF. Calculate the overall heat-transfer coefficient for the wall, the R value, and the heat loss per unit area.