Question

A three-layered wall with cross sectional area of 4.9 m² is composed of a 0.088 m thickness of cement (k = 0.3 W/(m*K)), a 0.186 m thickness of polyurethane foam (k = 0.03 W/(m*^oC)) and finally a 0.21 m thickness of glass (k = 0.8 W/(m*K)).

a) Calculate how much time is required for 0.06677 MJ of heat to flow through the wall given that the hot and cold sides of the wall are held at 25.4 ^oC and -8.7 ^oC.

Answer 1