Problem $1(20$ points$)$

Consider the wall shown below. The thermal resistance of the air space is equal to $R_{\text{a}\text{i}\text{r}}=0\mathrm{.}4m^2$

${?}^0\frac{C}{W}.$ Total wall area is $1m^2.$ Assume steady$-$state heat transfer and calculate the following items:

$(1)$ Overall thermal conductance $(5$ points$)$

$(2)$ Total heat transfer through the wall $(5$ points$)$

$(3)$ Surface temperatures of each wall layer $(5$ points$)$

$(4)$ Plot the temperatures from $(3)$ on the wall $(5$ points$)$