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Thread: Thermodynamic Properties of Water at Saturation

  1. #1

    Thermodynamic Properties of Water at Saturation

    I am looking for an explanation of the columns in Table 3 Thermodynamic Properties of Water at Saturation (Chapter 1 in Fundamentals) for specific volume.

    Three are listed.
    Sat. Solid
    vi/vf
    This appears to be the specific volume for saturated liquid.

    Evap.
    vig/vfg
    No clue.

    Sat. Vapor
    vg
    Pretty sure this is saturated vapor.

    I also need an explanation of the different specific volume variables. I know the meaning of:
    vi = specific volume of saturated solid (ice)
    vf = specific volume of saturated liquid (fluid)
    vg = specific volume of saturated vapor (gas)

    But what do
    vi/vf and vig/vfg mean, and how do they relate to the columns in the table?

    Thank you,

    Mike

  2. #2
    Occasional User Bill Bahnfleth's Avatar
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    Jun 2013
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    State College, Pennsylvania, USA
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    The headings are confusing, but not completely undecipherable. If you look at the notes at the bottom of Table 3, you will see that the subscript "i" in this table means a value for a temperature below the freezing point and a subscript "f" means a value for a temperature above the freezing point. If you consult the list of symbols, it says that subscripts "ig" and "fg" refer to differences between ice-water or saturated liquid-water vapor, respectively.

    What I gather is meant by a heading like:

    Specific Volume
    Sat. Solid
    v_i/v_f

    is that the column gives specific volume, represented by the symbol v_i if the temperature is below freezing and by v_f if it is above.

    Saturated vapor values are the sum of the the solid and phase change values, for example, h_g = h_fg+h_f
    Bill Bahnfleth
    Penn State
    Dept. of Architectural Engineering
    ASHRAE President 2013-14
    eMail: ashraepresident@ashrae.org
    Web: www.facebook.com/ASHRAEPresident

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