Question $1$

$($a$)$ A room has $80m^2$ of surface, of which $15m^2$ is to be heated, and the balance has an average surface temperature $17C.$ The air temperature in the room is $18C.$ The room is occupied by light clothed adults at rest. Determine the surface temperature of the heated panel necessary to produce comfort if the air velocity is $0\mathrm{.}1\frac{m}{s}.$ And comment on the result.

$(7$ Marks$)$

$($b$)$ What are the differences between gases and vapour?

$(2$ Marks$)$

$($c$)$ Suggest the characteristics of air jet.

$(5$ Marks$)$

$($d$)$ Suggest any three types of axial fan and comment on their characteristics.

$(6$ Marks$)$