Consider a multy$-$sorey building whose area equals $2020m^2.$

The building has $5$ storeys of $3$ meters high each and its windows occupy $30\%$ of the surface area of the multilayer plane walls.

The temperature outdoors is $0C$ and the temperature indoors is $20C.$

The U$-$value pertaining to the roof is $1,2$kca$\frac{l}{h}mC$ and the heat losses through the ground are $10$kca$\frac{l}{h}m{m}^2.$

The multilayer plane wall consists of $4$ layers:oi

$12-$cm thick ceramic brick layer $(k_{\text{b}\text{r}\text{i}\text{c}\text{k}}=0,60$kca$\frac{l}{h}mK).$

The window consists of a $6-$mm thick glass pane whose conductivity equals $k_{\text{b}\text{r}\text{i}\text{c}\text{k}}=0,66$kca$\frac{l}{h}mC.$

The internal and external film coefficients are:

Internal: $h_i=7$kca$\frac{l}{h}{m}^{2}C.$

External: $h_0=20$kca$\frac{l}{h}{m}^{2}C.$

The temperature of the internal surface of the wall is $370C$ and the temperature of the external surface of the wall is $66C.$

Please determine: $$

The heat losses of the building.

The temperature of the external surface of the wall.

The temperature of the internal surface of the window glass.

If the exterior temperature of one of the walls were $18$ degrees, determine the heat flux exchange by radiation. The emissivity of the material is $lon=0,75$ and the Stefan$-$Boltzman's constant is $=5,{6710}^{-8}W{m}^{-2}{K}^{-4}).$