i. Inside conditions 24°C DBT, 55% RH

ii. Outside conditions 37°C DBT, 25°C WBT

iii. Sensible heat gain 13.6kW

iv. Latent heat gain 8.25kW

Return air is mixed with outdoor air before entering coil in ratio 3.5:1 and return from room is also mixed after cooling coil in ratio 1:3.5 Coil BPF is 0.15 Air may be reheated if necessary before supplying to conditioned room. Assuming ADP 7°C. Determine:

a) Supply air condition to the room

b) Amount of fresh air supplied

c) Cooling load

Subject:- Refrigeration and Air Conditioning

Topic:- Design of air conditioning systems

Difficulty:- Low

$t_d2=24℃,∅2=55%, t_d1=37℃, t_w1=25℃,ADP=7℃,$

RSH=13.6 kW,RLH=8.25 kW, BPF=0.15

Locate points 1 and 2 on psychrometric chart. Since return air from room and outside air are mixed before entering cooling coil in ratio 3.5:1, therefore mark this point 3 on line 1-2 as

length(23)=$\frac{length(21)}{4.5}$

From psychrometric chart,

$t_d3=27℃$ and h3=56 $\frac{kJ}{kg} $of …