In: Physics
A wall in a building has a width of 15 m and a height of 3 m. It is made of several layers — a layer of motionless air with an R value of 0.12 K m^2 / W, a 12.4 mm thick layer of gypsum board with a thermal conductivity of 0.17 W/m K, a layer of brick with an R value of 1.7 m^2/ W, and another layer of motionless air with an R value of 0.12 K m^2 / W.
(a) If the temperature inside the building is 27.2 °C and the temperature outside is 33.1 °C, how much power will flow through the wall in steady state?
(b) How much power will flow if we add a layer of foam insulation with an R value of 27.0 K m2/ W?