Window type #$5$b with fixed aluminum frame in Table $5\mathrm{.}1$ is located on the south$-$facing vertical wall, that is $2$ m tall and $3$ m wide. The latitude is $33N$ :

a$)$ Find the global irradiance at noon on June $21$ when beam normal irradiance is $900\frac{W}{m^2}[285\mathrm{.}3$ Btu$/($h $*($:$f{t}^2$