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Thread: True or False?

  1. #14
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    now about this

    indoor ambient 90*F 80% R/H
    outdoor ambient 103*F

    whats the coil temp. and whats the leaving air R/H?
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  2. #15
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    What's the dog's name again?

  3. #16
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    Unfair, that's not true or false.
    Last edited by Jay 41; 06-09-2008 at 10:13 PM. Reason: mis-spell

  4. #17
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    Its not a theory... its a fact... look it up

  5. #18
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    http://efficientcomfort.net/jsp/PsychroCoilCalc_Web.jsp


    try it out......unless your coil is dry....mine moves lots of gallons of moisture.

  6. #19
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    I sure hope so... but the point is that the warmer air is the more moisture it holds... so air at 75 degrees holds more moisture than 55 degree air. Air cooled below the dewpoint is at 100% humidity.

  7. #20
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    Quote Originally Posted by BigJon3475 View Post
    Bypass factor


    never seen wb and db temps the same exiting the evap


    Your theory would be correct if you could have 100% of the air move across the surface of the coil.
    That is correct BigJon. Some air does not contact the fins, hence the air will Be about 95% RH. Only if you had 100% coil contact would the answer be true. The coil manufacturers are getting closer but are not there yet.

    In theory it should be true, but in practice it is false.
    Remember, Air Conditioning begins with AIR.

  8. #21
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    If you can get 100% of the air to move across coil surface.

    That's not possible as far as I know.

    You will be left with some air that is not conditioned at all.......I have done it many times......very close to 100% RH.......never 100%......in a true or false question asking for 100% and actually seeing 99.9% makes it false.

  9. #22
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    lol

    Close to 100%,like I said before.

  10. #23
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    Quote Originally Posted by air-doctor View Post
    What's the dog's name again?
    Mimi
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  11. #24
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    So your argument is that because less than 100% of the air contacts the coil surfaces the air temperature leaving the evaporator is not cooled below the dewpoint?

  12. #25
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    enlighten me if I'm wrong....I can only go by real world exp.



    if 80&#37; of the air contacts the coil and is dehumidified and sensibly cooled....then your left with 20% that was not 100% saturated.......add that to the equation......I can't think of any other way it comes out other than <100% saturated.

  13. #26
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    Simple physics... if air is cooled below the dewpoint it is at 100% humidity. I'll admit that its kind of a trick question... but its a fact nonetheless

    Dew point
    From Wikipedia, the free encyclopedia
    The dew point (sometimes spelled dewpoint) is the temperature to which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water. The condensed water is called dew. The dew point is a saturation point.

    When the dew point temperature falls below freezing it is called the frost point, as the water vapor no longer creates dew but instead creates frost or hoarfrost by deposition.

    The dew point is associated with relative humidity. A high relative humidity indicates that the dew point is closer to the current air temperature; if the relative humidity is 100%, the dew point is equal to the current temperature. Given a constant dew point, an increase in temperature will lead to a decrease in relative humidity.

    At a given barometric pressure, independent of temperature, the dew point indicates the mole fraction of water vapor in the air, and therefore determines the specific humidity of the air.

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