Final answer:
The heat flow through a house wall must be calculated by considering the overall thermal resistance and the presence of wooden studs, which affect the wall's thermal properties.
Step-by-step explanation:
The question refers to calculating the rate of heat flow through a house wall with specific construction details and materials. For part (a), we need to consider the overall thermal resistance (R-value) of the layers to find the heat flow due to the temperature difference.
This calculation is grounded in the principles of thermodynamics and heat transfer. For part (b), the presence of 2-by-4 studs in the wall needs to be taken into account, which will alter the thermal resistance and consequently change the heat flow rate.
As studs have a different thermal resistance compared to fiberglass insulation, separate calculations are needed for the portions of the wall with studs and for the portions with only insulation. Since the studs are placed on 16-inch centers, this spacing will inform the proportion of the wall they occupy.
For accurate calculations, the heat flow through the studs and insulation must be calculated separately and then combined according to their respective proportions. The question also includes consideration for the half-thickness of exterior walls, indicating a simplified approach to the calculation by assuming the exterior temperature gradient only applies to half the wall's thickness.