Question

In this problem you will estimate the heat lost by a typical house,assuming that the temperature inside is T(in) = 20*C and thetemperature outside is T(out) = 0*C. The walls have fiberglassinsulation, which dominates the heat conduction properties of thewall So we can consider the wall to have a thermal conductivity ofk(wall) = 0.048 W/m/K. We will take the thickness of the walls andceiling to be L(wall) = 12 cm. Assume that the house is a cube oflength L = 9.0 m on a side. Assume that the roof has very highconductivity, so that the air in the attic is at the sametemperature as the outside air. Ignore heat loss through theground.



a)What is H, the total rate of energy loss due to heat conductionfor this house?

b)Let us assume that the winter consists of 150 days in which theoutside temperature is 0*C on average. This will give the typicalnumber of "heating degree days" observed in a winter in Vancouver.Given that heating oil has an energy content of 35 MJ per litrewhen burned, how much oil will be needed to supply the heat lost byconduction from this house over a winter? Assume that the heatingsystem is 75% efficient.