Results 1 to 5 of 5
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01-06-2005, 10:48 AM #1
leaving dry and wet bulb difference of Evaporator coil
One of the enquiries from the consultant came 2 me for DX coil
Conditions were
Air IN 87.7F/59.2F (DB/WB)
Leaving 59.3F/47.5F (DB/WB)
CFM 5000
Capacity 153000BTU/hr
I am confused over the difference in DB and WB of leaving temperature Is it POSSIBLE?
Our nose is our personal air-conditioning system: it warms cold air, cools hot air and filters impurities
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01-06-2005, 12:42 PM #2
Re: leaving dry and wet bulb difference of Evaporator coil
for the figures you gave you would get:
Sensible heat load = 153,610.1 BTU
Latent Heat Load = -6255.5 BTU
Total Heat Load = 147,354.7 BTU
I would suspect the readings as you have negative latent heat..in other words the evap is giving up latent heat......100% is possible 100% of the time
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01-06-2005, 12:55 PM #3
Re: leaving dry and wet bulb difference of Evaporator coil
For your air in/out you have:
air in air out
Dew point = 34.8F 35F
RH = 15.2% 40%
H/Ratio w .00422lb water/lb dry air .00427
H/R g 29.6 grains 29.9g
SV 13.833 cu ft/lb 13.174
Enthalpy 25.69BTU/lb 18.87
Hope these mean something to you.....100% is possible 100% of the time
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02-06-2005, 05:12 AM #4
Re: leaving dry and wet bulb difference of Evaporator coil
tell u what guys i think it is dry surface cooling.
My question was how does this happen.
I know how 2 select the coil. you may see the attachment.Our nose is our personal air-conditioning system: it warms cold air, cools hot air and filters impurities
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10-06-2005, 12:25 AM #5
Re: leaving dry and wet bulb difference of Evaporator coil
Seems pretty straightforward to me. The entering dewpoint is about 35F. Dew (moisture) is only going to condense on a surface that is colder than dewpoint. The coil surface was not cold enough to extract moisture, therefore you have a dry coil.
The leaving air, not having lost any moisture, still has a dewpoint of about 35F.
34.8 vs 35 is instrument error.Last edited by Gary; 10-06-2005 at 12:28 AM.