$7\mathrm{.}27$ Figure P$7\mathrm{.}27$ provides steady$-$state data for the outer wall of a dwelling on a day when the indoor temperature is maintained at $20$C

and the outdoor temperature is $0$C$.$ The heat transfer rate through the wall is $1100$ W$.$ Determine, in W$,$ the rate of exergy destruction

$($a$)$ within the wall, and $($b$)$ within the enlarged system shown on the figure by the dashed line. Comment. Let To $=0$C$.$