$17-22$ Consider a $1\mathrm{.}5-$m$-$high and $2\mathrm{.}4-$m$-$wide double$-$

pane window consisting of two $3-$mm$-$thick layers of glass

$(k=0\mathrm{.}78\frac{W}{m}*K)$ separated by a $12-mm-$wide stagnant airspace

$)=(0\mathrm{.}026\frac{W}{m}*K.$ Determine the steady rate of heat transfer

through this double$-$pane window and the temperature of its inner

surface for a day during which the room is maintained at $21C$

while the temperature of the outdoors is $-5C.$ Take the con$-$

vection heat transfer coefficients on the inner and outer surfaces

of the window to be $h_1=10\frac{W}{m^2}*K$ and $h_2=25\frac{W}{m^2}*K,$ and

disregard any heat transfer by radiation. Answers: $154W,16\mathrm{.}7C$

FIGURE P$17-22$