The room cooling load of an office is 60kW total, 48.7kW sensible. The indoor co
ID: 2291945 • Letter: T
Question
The room cooling load of an office is 60kW total, 48.7kW sensible. The indoor condition is to be maintained at 24°C/50%RH by an Air Handling Unit, calculate the required supply air flow rate if the off-coil condition is 13°C / 90%RH. Now that the design outdoor condition is 33°C dry bulb 27°C wet bulb. It is expected that there will be 50 persons working in this office. Each person should be supplied with 10/s fresh air. Calculate the required fresh air flow rate. The fresh air is first mixed with the room return air and cooled by the cooling coil of the Air Handling Unit. The cooled air is then supplied to the room. Calculate the fresh air l return air mixing condition.Explanation / Answer
Room total load is 60kw.
Room sensible heat is 48.7kw.
so effective sensible heat factor of the room will be = room sensible heat / room total heat
= 48.7 / 60
=0.811
i.e., the room is having 81% of sensible heat and 19% of latent heat.
to maintain 24-degree Celsius with 50% of relative humidity the apparatus dew point will be 10.5 degree Celsius.
to maintain 13-degree Celsius with 90% of relative humidity the apparatus dew point will be 10.5-degree Celsius.
Dehumidified air rise = (1-bypass factor) * (room dry bulb temperature - selected apparatus dew point)
= (1 - 0.1) * (24 - 10.5 )
= 0.9 * 13.5
= 12.15 celsius
dehumidified air quantity = effective room sensible heat / (1.08 * dehumidified air rise )
the required supply air flow rate is 341.40 Liters per second
the outside temperature is 33 degree celsicus dry bulb temperature
number of persons working will be 50 persons
fresh air for each person is 10 l/s
so for 50 people its 500 l/s
Mixed Air Temperature (?F), tmix [(Total Return Air x l/s Return Air)+(Total Fresh Air x l/s Fresh Air)] / l/s Supply air
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.