An experimental test chamber, inside dimensions $20$ m x $10$ m x $3$ m high is to be maintained at $300$C$.$ The walls and roof consist of brick $120$ mm thick insulated with glass wool $80$ mm thick protected on the outside by timber $40$ mm thick. The surrounding atmospheric temperature is $20$oC$.$Determine the power necessary to keep the chamber at a constant temperature through the wall only, using the following data:

$$thermal conductivity of brick $1\mathrm{.}4$ W$/($m K$)$

$$thermal conductivity of glass wool $0\mathrm{.}043$ W$/($m K$)$

$$thermal conductivity of timber $0\mathrm{.}11$ W$/($m K$)$

$$heat transfer coefficient for outer vertical surfaces $1\mathrm{.}62$ W$/($m$2$ K$)$

$$heat transfer coefficient for outer roof surface $3\mathrm{.}35$ W$/($m$2$ K$)$

Question $1$Select one:

a$.$

$17236\mathrm{.}8$ W

b$.$

$1723\mathrm{.}68$ W

c$.$

$172\mathrm{.}368$ W