A building has a 2.4 m deep basement (foundation) wall that is 100 m long. The wall has no windows. On average, 2.1 m of the wall is below grade (underground). Assume the outside air temperature is - 10°C, the inside temperature is 20°C, and the average ground temperature is 10°C.
a. Determine the rate of heat loss through the wall below grade if it is uninsulated.
b. Determine the rate of heat loss through the wall below grade if it is insulated with an R-value of about 2.2°C · m²/W.