Q$2.$ Outdoor air $(1)$ is available at $5C$ DB and $20\%RH.$ The outdoor air flows at $2\mathrm{.}0k\frac{g}{s}$ and is

preheated with $10$ kW of sensible heat $(1^{\text{'}})$ before being mixed with return air $(2).$ The mixture of

preheated outdoor and return air is supplied to the AC apparatus $(3)$ at $18C$ DB$.$ The room $(2)$

is to be maintained at $20C$ DB and $50\%RH.$ Air is supplied $(4)$ to the room at $30C$ DB and a

humidity ratio of $8\frac{g}{k}g.$ For simplicity use $c_p=1k\frac{J}{k}g*K.$

a$)$ Estimate the temperature of the outdoor air after it has been preheated $(1\text{'}).$

b$)$ Using an energy balance, or otherwise, estimate the dry air mass flow rate of return air $(2).$

c$)$ Estimate the dry air mass flow rate of air supplied to the AC apparatus $(3).$

d$)$ Estimate the RSHF from the Psychrometric chart.

e$)$ Estimate the room sensible heating load.

f$)$ Estimate the room latent heating load.

g$)$ Estimate the required mass flow rate of water supplied by the AC apparatus $($humidification

rate$).$

h$)$ Estimate the total heating load required by the $AC$ system including the preheat.

Plot the process on a Psychrometric chart.