1) A composite exterior wall has 3 main layers in series as shown in the figure....

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1) A composite exterior wall has 3 main layers in series as shown in the figure. The thicknesses of layers are LA-10 mm, La-150 mm and Le 20 mm. In a cold winter day, indoor and outdoor temperatures are measured as T-22C and T -20C; while indoor and outdoor convective heat transfer coefficients are known to be h-5 W/mK and h,-25 W/mK, respectively. The thermal conductivity of materials are kA-0.7 W/mK. kB 1.3 W/mK and kc 0.5 W/mK. Neglecting the contact surface resistance and assuming steady-state one-dimensional heat transfer; a) Sketch the thermal circuit and find the total thermal resistance per unit area (Ret") (20 pts) b) Determine the total heat flux through the wall (q") (10 pts) e) Find the outer surface temperature (T.)(10 pts) d) If an insulating sheet is added as 4th layer (Layer D) at the outer side, having the properties of LD-10 mm and ko 0.02 W/m K. find the heat flux through the wall for the new case. (10 pts) T -22C 5W-K B 1. T., = -20C A = 25 W/m-K 1) A composite exterior wall has 3 main layers in series as shown in the figure. The thicknesses of layers are LA-10 mm, La-150 mm and Le 20 mm. In a cold winter day, indoor and outdoor temperatures are measured as T-22C and T -20C; while indoor and outdoor convective heat transfer coefficients are known to be h-5 W/mK and h,-25 W/mK, respectively. The thermal conductivity of materials are kA-0.7 W/mK. kB 1.3 W/mK and kc 0.5 W/mK. Neglecting the contact surface resistance and assuming steady-state one-dimensional heat transfer; a) Sketch the thermal circuit and find the total thermal resistance per unit area (Ret") (20 pts) b) Determine the total heat flux through the wall (q") (10 pts) e) Find the outer surface temperature (T.)(10 pts) d) If an insulating sheet is added as 4th layer (Layer D) at the outer side, having the properties of LD-10 mm and ko 0.02 W/m K. find the heat flux through the wall for the new case. (10 pts) T -22C 5W-K B 1. T., = -20C A = 25 W/m-K

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a The thermal circuit for the composite exterior wall can be represented as follows gherkin Copy L L ... View the full answer