How do I calculate my membrane output?

Discussion in 'SpectraPure' started by SpectraPure, Nov 6, 2009.

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  1. SpectraPure

    SpectraPure 3reef Sponsor

    Joined:
    Sep 10, 2009
    Messages:
    25

    How do I calculate my membrane output?
    Membranes produce the rated gallons per day (GPD) at 60 psi (4.1 bars)
    operating pressure, 77°F (25°C) operating temperature and 500 ppm total dissolved solids.
    Membrane output gallons per day (GPD) depends on operating pressure, water temperature and the ppm TDS in the feed water.
    Expected GPD = Rated GPD × PCF × TCF
    PCF is the pressure correction factor
    TCF is the temperature correction factor

    Calculation of Pressure Correction Factor (PCF): The output (GPD) from
    the membrane is directly proportional to the applied pressure.
    Note: The membrane is rated to produce the rated GPD at 60 psi. For any pressure
    other than 60 psi the output GPD is multipled by the PCF.
    PCF = Line Pressure (in psi) ÷ 60

    Calculation of Temperature Correction Factor (TCF): The output (GPD)
    also decreases with decrease in temperature. This is because water viscosity
    increases with decrease in water temperature.
    Temperature Correction Factor Table (TCF)
    °F /°C TCF °F \°C TCF °F \°C TCF
    41.0 /5 0.521 59.0 /15 0.730 77.0 /25 1.000
    42.8 /6 0.540 60.8 /16 0.754 78.8 /26 1.031
    44.6 /7 0.560 62.6 /17 0.779 80.6 /27 1.063
    46.4 /8 0.578 64.4 /18 0.804 82.4 /28 1.094
    48.2 /9 0.598 66.2 /19 0.830 84.2 /29 1.127
    50.0 /10 0.620 68.0 /20 0.857 86.0 /30 1.161
    51.8 /11 0.640 69.8 /21 0.884 87.8 /31 1.196
    53.6 /12 0.661 71.6 /22 0.912 89.6 /32 1.232
    55.4 /13 0.684 73.4 /23 0.941 91.4 /33 1.267
    57.2/14 0.707 75.2 /24 0.970 93.2 /34 1.304