aungkyawtun
Mechanical
sensible heat gain is 108 kW.installed ahu is 103 kW@ 5.3 cmh. what will be the room temperature .100% return air system
Thank u in advance
Thank u in advance
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undersized ac vs room temperature
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LittleInch
Petroleum
Hot.
No where near enough info. Is this a school question?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
No where near enough info. Is this a school question?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
reset the room temperature in your heat load software until you get a sensible cooling load of 103kW, noting you need to also check the change in sensible capacity as air-on conditions change.
But then read ANSI/AHRI STANDARD 210/240-2008 "Performance Rating of Unitary Air-Conditioning & Air-Source Heat Pump Equipment" and realise what the allowable margin is on stated capacity and an AHU with 103kW capacity, could legally be doing quite a bit more (or less) and so what is the real capacity of the unit?
But in the real world with a conservative 10% safety factors etc, for most of the year, you would be able to achieve the design room temp in any case.
But then read ANSI/AHRI STANDARD 210/240-2008 "Performance Rating of Unitary Air-Conditioning & Air-Source Heat Pump Equipment" and realise what the allowable margin is on stated capacity and an AHU with 103kW capacity, could legally be doing quite a bit more (or less) and so what is the real capacity of the unit?
But in the real world with a conservative 10% safety factors etc, for most of the year, you would be able to achieve the design room temp in any case.
RandomUserName
Mechanical
I round a lot.
Assume:
Qs = 108 kW (368 MBH)
Qhvac = 103 kW (351 MBH)
RA = 75°F
SA = 58°F
Qhvac is 100% sensible load capacity; also includes fan heat gain
100 % RA system with no OA; therefore RA = MA
Qhvac = (1.08)(CFM)(deltaT)
CFM = (Qhvac)/(1.08)/(deltaT)
CFM = (351,000 BTU/hr)/(1.08)/(75-58°F)
CFM = 19,100 CFM
Holding CFM constant:
Qs = (1.08)(CFM)(deltaT)
deltaT = (Qs)/(1.08)/(CFM)
deltaT = (368,000 BTU/hr)/(1.08)/(19,100 CFM)
deltaT = 17.8°F
RA = SA + deltaT
RA = 58°F + 17.8°F
RA = 75.8°F
Seems negligible unless critical.
Assume:
Qs = 108 kW (368 MBH)
Qhvac = 103 kW (351 MBH)
RA = 75°F
SA = 58°F
Qhvac is 100% sensible load capacity; also includes fan heat gain
100 % RA system with no OA; therefore RA = MA
Qhvac = (1.08)(CFM)(deltaT)
CFM = (Qhvac)/(1.08)/(deltaT)
CFM = (351,000 BTU/hr)/(1.08)/(75-58°F)
CFM = 19,100 CFM
Holding CFM constant:
Qs = (1.08)(CFM)(deltaT)
deltaT = (Qs)/(1.08)/(CFM)
deltaT = (368,000 BTU/hr)/(1.08)/(19,100 CFM)
deltaT = 17.8°F
RA = SA + deltaT
RA = 58°F + 17.8°F
RA = 75.8°F
Seems negligible unless critical.
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