Answer:
dimensions and materials information that are provided about composite wall (2.5mx6.5m 10 studs each 2.5m high)
to find:wall thermal resistance=??
properties:
Ka=0.094W/m.K
Kb=0.16W/m.K
Kc=0.17W/m.K
Kd=0.038W/m.K
using isothermal surface assumption:
(La/KaAa)=0.008/0.094(0.65x2.5)
=0.0524K/W
(LB/KbAb)=0.13/0.16(0.04x2.5)
=8.125K/W
(Ld/KdAd)=0.13/0.38(0.6x2.5)
=2.243K/W
core's equivalent resistance is:
Req=(1/Rb+1/Rd)⁻¹
=(1/8.125+1/2.243)⁻¹
=1.758K/W
For total resistance we will find sum of
Rtot=Ra+Req+Rc
=1.854K/W
Whereas 10 studs are used so:
Rtotal=(10x1/Rtot)⁻¹
=0.1854K/W