A summer air conditioning system receives fresh air from the outside at 45°C and 50% RH,

A summer air conditioning system receives fresh air from the outside at 45°C and 50% RH, and
the room (20 m × 20 m × 4 m) is to be kept at 25°C and 50%. There are 50 people in the room
with an average metabolic rate of 130 W. The infiltration rate is 10 m3/min and the ventilation
rate is 0.4 m3/min/person. The walls of the room are made up of 1” thick maple hardwood on
each side with a 6” fiberglass insulation in between. The room has 60 m2 windows and a solar
radiation comes inside the room at the rate of 900 W/m2 through them. For this problem, you can
ignore the effect of solar radiation incident on the outer walls of the room. The outside convection
heat transfer coefficient is 25 W/m2–K and the same for the inside is 10 W/m2–K. The room has
the lighting load of 10 kW and the equipment load of 25 kW.
The HVAC system looks like as shown below. The apparatus dew point temperature for the
cooling coil is 10°C with a BPF of 0.2. For this system
1. Find the state of air at 2
2. Find the state of air at 3 and mass of fresh air coming in if
a. The recirculation fraction is 0%
b. The recirculation fraction is 100%
c. The recirculation fraction is 50%
3. Cooling coil capacity