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water_use

SECDAY = 86400.0 module-attribute

WaterUse

Source code in process/models/water_use.py 
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class WaterUse:
    def __init__(self):
        self.outfile = constants.NOUT

    def run(self, output: bool):
        """Routine to call the water usage calculation routines.
        This routine calls the different water usage routines.

        Parameters
        ----------
        output :
            indicate whether output should be written to the output file, or not
        """
        rejected_heat = heat_transport_variables.p_plant_primary_heat_mw * (
            1 - heat_transport_variables.eta_turbine
        )

        wastethermeng = rejected_heat * SECDAY

        if output:
            po.oheadr(
                self.outfile, "Water usage during plant operation (secondary cooling)"
            )
            po.ocmmnt(
                self.outfile,
                "Estimated amount of water used through different cooling system options:",
            )
            po.ocmmnt(self.outfile, "1. Cooling towers")
            po.ocmmnt(
                self.outfile,
                "2. Water bodies (pond, lake, river): recirculating or once-through",
            )

        # call subroutines for cooling mechanisms:

        # cooling towers
        self.cooling_towers(wastethermeng, output=output)

        # water-body cooling
        self.cooling_water_body(wastethermeng, output=output)

    def cooling_towers(self, wastetherm: float, output: bool):
        """Water used in cooling towers

        Parameters
        ----------
        wastetherm:
            thermal energy (MJ) to be cooled by this system
        output:

        """
        water_usage_variables.evapratio = 1.0e0 - (
            (
                -0.000279e0 * water_usage_variables.airtemp**3
                + 0.00109e0 * water_usage_variables.airtemp**2
                - 0.345e0 * water_usage_variables.airtemp
                + 26.7e0
            )
            / 100.0e0
        )
        # Diehl et al. USGS Report 2013-5188, http://dx.doi.org/10.3133/sir20135188

        water_usage_variables.volheat = (
            water_usage_variables.waterdens * water_usage_variables.latentheat
        )

        water_usage_variables.energypervol = (
            water_usage_variables.volheat / water_usage_variables.evapratio
        )

        water_usage_variables.volperenergy = (
            1.0e0 / water_usage_variables.energypervol * 1000000.0e0
        )

        water_usage_variables.evapvol = wastetherm * water_usage_variables.volperenergy

        # find water withdrawn from external source
        water_usage_variables.waterusetower = 1.4e0 * water_usage_variables.evapvol
        # Estimated as a ratio to evaporated water (averaged across observed dataset)
        #  as per Diehl et al. USGS Report 2014-5184, http://dx.doi.org/10.3133/sir20145184

        # end break

        #  Output section
        if output:
            po.ovarre(
                self.outfile,
                "Volume used in cooling tower (m3/day)",
                "(waterusetower)",
                water_usage_variables.waterusetower,
                "OP ",
            )

    def cooling_water_body(self, wastetherm: float, output: bool):
        """Water evaporated in cooling through water bodies
        Based on spreadsheet from Diehl et al. USGS Report 2013-5188, which includes
        cooling coefficients found through fits across a dataset containing a wide range of
        temperatures, windspeeds, and heat loading:
        http://pubs.usgs.gov/sir/2013/5188/appendix/sir2013-5188_appendix4_fews_version_3.104.xlsx


        Parameters
        ----------
        wastetherm:
            thermal energy (MJ) to be cooled by this system
        output:

        """
        evapsum = 0.0e0

        for icool in range(1, 4):
            if icool == 1:
                # small pond as a cooling body
                # heat loading, MW/acre, based on estimations from US power plants
                heatload = 0.35e0
                # coefficients as per Brady et al. 1969:
                # wind function coefficients
                a = 2.47e0
                b = 0e0
                c = 0.12e0
                # fitted coefficients of heat loading
                d = 3061.331e0
                e = -48.810e0
                f = -78.559e0
                g = -291.820e0
                h = 0.267e0
                i = -0.610e0
                j = 33.497e0

            elif icool == 2:
                # large lake or reservoir as a cooling body
                # heat loading, MW/acre, based on estimations from US power plants
                heatload = 0.10e0
                # coefficients as per Webster et al. 1995:
                # wind function coefficients
                a = 1.04e0
                b = 1.05e0
                c = 0.0e0
                # fitted coefficients of heat loading
                d = 3876.843e0
                e = -49.071e0
                f = -295.246e0
                g = -327.935e0
                h = 0.260e0
                i = 10.528e0
                j = 40.188e0

            elif icool == 3:
                # stream or river as a cooling body
                # heat loading, MW/acre, based on estimations from US power plants
                heatload = 0.20e0
                # coefficients as per Gulliver et al. 1986:
                # wind function coefficients
                a = 2.96e0
                b = 0.64e0
                c = 0.0e0
                # fitted coefficients of heat loading
                d = 2565.009e0
                e = -43.636e0
                f = -93.834e0
                g = -203.767e0
                h = 0.257e0
                i = 2.408e0
                j = 20.596e0

            # Unfortunately, the source spreadsheet was from the US, so the fits for
            #   water body heating due to heat loading and the cooling wind functions
            #   are in non-metric units, hence the conversions required here.
            # Limitations: maximum wind speed of ~5 m/s; initial water_usage_variables.watertemp < 25 degC

            # convert water_usage_variables.windspeed to mph
            water_usage_variables.windspeedmph = (
                water_usage_variables.windspeed * 2.237e0
            )

            # convert heat loading into cal/(cm2.sec)
            heatloadimp = heatload * 1000000.0e0 * 0.239e0 / 40469000.0e0

            # estimate how heat loading will raise temperature, for this water body
            heatratio = (
                d
                + (e * water_usage_variables.watertemp)
                + (f * water_usage_variables.windspeedmph)
                + (g * heatload)
                + (h * water_usage_variables.watertemp**2)
                + (i * water_usage_variables.windspeedmph**2)
                + (j * heatload**2)
            )

            # estimate resultant heated water temperature
            water_usage_variables.watertempheated = water_usage_variables.watertemp + (
                heatloadimp * heatratio
            )

            # find wind function, m/(day.kPa), applicable to this water body:
            windfunction = (
                a
                + (b * water_usage_variables.windspeed)
                + (c * water_usage_variables.windspeed**2)
            ) / 1000.0e0

            # difference in saturation vapour pressure (Clausius-Clapeyron approximation)
            satvapdelta = (
                0.611e0
                * np.exp(
                    (17.27e0 * water_usage_variables.watertempheated)
                    / (237.3e0 + water_usage_variables.watertempheated)
                )
            ) - (
                0.611e0
                * np.exp(
                    (17.27e0 * water_usage_variables.watertemp)
                    / (237.3e0 + water_usage_variables.watertemp)
                )
            )

            # find 'forced evaporation' driven by heat inserted into system
            deltae = (
                water_usage_variables.waterdens
                * water_usage_variables.latentheat
                * windfunction
                * satvapdelta
            )

            # convert heat loading to J/(m2.day)
            heatloadmet = heatload * 1000000.0e0 / 4046.85642e0 * SECDAY

            # find evaporation ratio: ratio of the heat used to evaporate water
            #   to the total heat discharged through the tower
            water_usage_variables.evapratio = deltae / heatloadmet
            # Diehl et al. USGS Report 2013-5188, http://dx.doi.org/10.3133/sir20135188

            water_usage_variables.volheat = (
                water_usage_variables.waterdens * water_usage_variables.latentheat
            )

            water_usage_variables.energypervol = (
                water_usage_variables.volheat / water_usage_variables.evapratio
            )

            water_usage_variables.volperenergy = (
                1.0e0 / water_usage_variables.energypervol * 1000000.0e0
            )

            water_usage_variables.evapvol = (
                wastetherm * water_usage_variables.volperenergy
            )

            # using this method the estimates for pond, lake and river evaporation produce similar results,
            #   the average will be taken and used in the next stage of calculation
            evapsum = evapsum + water_usage_variables.evapvol

        evapsum = evapsum / icool

        # water volume withdrawn from external source depends on recirculation or 'once-through' system choice
        #   Estimated as a ratio to evaporated water (averaged across observed dataset)
        #   as per Diehl et al. USGS Report 2014-5184, http://dx.doi.org/10.3133/sir20145184

        # recirculating water system:
        water_usage_variables.wateruserecirc = 1.0e0 * evapsum

        # once-through water system:
        water_usage_variables.wateruseonethru = 98.0e0 * evapsum

        # end break

        #  Output section
        if output:
            po.ovarre(
                self.outfile,
                "Volume used in recirculating water system (m3/day)",
                "(wateruserecirc)",
                water_usage_variables.wateruserecirc,
                "OP ",
            )
            po.ovarre(
                self.outfile,
                "Volume used in once-through water system (m3/day)",
                "(wateruseonethru)",
                water_usage_variables.wateruseonethru,
                "OP ",
            )

outfile = constants.NOUT instance-attribute

run(output)

Routine to call the water usage calculation routines. This routine calls the different water usage routines.

Parameters:

Name Type Description Default
output bool

indicate whether output should be written to the output file, or not

 required
Source code in process/models/water_use.py 
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def run(self, output: bool):
    """Routine to call the water usage calculation routines.
    This routine calls the different water usage routines.

    Parameters
    ----------
    output :
        indicate whether output should be written to the output file, or not
    """
    rejected_heat = heat_transport_variables.p_plant_primary_heat_mw * (
        1 - heat_transport_variables.eta_turbine
    )

    wastethermeng = rejected_heat * SECDAY

    if output:
        po.oheadr(
            self.outfile, "Water usage during plant operation (secondary cooling)"
        )
        po.ocmmnt(
            self.outfile,
            "Estimated amount of water used through different cooling system options:",
        )
        po.ocmmnt(self.outfile, "1. Cooling towers")
        po.ocmmnt(
            self.outfile,
            "2. Water bodies (pond, lake, river): recirculating or once-through",
        )

    # call subroutines for cooling mechanisms:

    # cooling towers
    self.cooling_towers(wastethermeng, output=output)

    # water-body cooling
    self.cooling_water_body(wastethermeng, output=output)

cooling_towers(wastetherm, output)

Water used in cooling towers

Parameters:

Name Type Description Default
wastetherm float

thermal energy (MJ) to be cooled by this system

 required
output bool
required
Source code in process/models/water_use.py 
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def cooling_towers(self, wastetherm: float, output: bool):
    """Water used in cooling towers

    Parameters
    ----------
    wastetherm:
        thermal energy (MJ) to be cooled by this system
    output:

    """
    water_usage_variables.evapratio = 1.0e0 - (
        (
            -0.000279e0 * water_usage_variables.airtemp**3
            + 0.00109e0 * water_usage_variables.airtemp**2
            - 0.345e0 * water_usage_variables.airtemp
            + 26.7e0
        )
        / 100.0e0
    )
    # Diehl et al. USGS Report 2013-5188, http://dx.doi.org/10.3133/sir20135188

    water_usage_variables.volheat = (
        water_usage_variables.waterdens * water_usage_variables.latentheat
    )

    water_usage_variables.energypervol = (
        water_usage_variables.volheat / water_usage_variables.evapratio
    )

    water_usage_variables.volperenergy = (
        1.0e0 / water_usage_variables.energypervol * 1000000.0e0
    )

    water_usage_variables.evapvol = wastetherm * water_usage_variables.volperenergy

    # find water withdrawn from external source
    water_usage_variables.waterusetower = 1.4e0 * water_usage_variables.evapvol
    # Estimated as a ratio to evaporated water (averaged across observed dataset)
    #  as per Diehl et al. USGS Report 2014-5184, http://dx.doi.org/10.3133/sir20145184

    # end break

    #  Output section
    if output:
        po.ovarre(
            self.outfile,
            "Volume used in cooling tower (m3/day)",
            "(waterusetower)",
            water_usage_variables.waterusetower,
            "OP ",
        )

cooling_water_body(wastetherm, output)

Water evaporated in cooling through water bodies Based on spreadsheet from Diehl et al. USGS Report 2013-5188, which includes cooling coefficients found through fits across a dataset containing a wide range of temperatures, windspeeds, and heat loading: http://pubs.usgs.gov/sir/2013/5188/appendix/sir2013-5188_appendix4_fews_version_3.104.xlsx

Parameters:

Name Type Description Default
wastetherm float

thermal energy (MJ) to be cooled by this system

 required
output bool
required
Source code in process/models/water_use.py 
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def cooling_water_body(self, wastetherm: float, output: bool):
    """Water evaporated in cooling through water bodies
    Based on spreadsheet from Diehl et al. USGS Report 2013-5188, which includes
    cooling coefficients found through fits across a dataset containing a wide range of
    temperatures, windspeeds, and heat loading:
    http://pubs.usgs.gov/sir/2013/5188/appendix/sir2013-5188_appendix4_fews_version_3.104.xlsx


    Parameters
    ----------
    wastetherm:
        thermal energy (MJ) to be cooled by this system
    output:

    """
    evapsum = 0.0e0

    for icool in range(1, 4):
        if icool == 1:
            # small pond as a cooling body
            # heat loading, MW/acre, based on estimations from US power plants
            heatload = 0.35e0
            # coefficients as per Brady et al. 1969:
            # wind function coefficients
            a = 2.47e0
            b = 0e0
            c = 0.12e0
            # fitted coefficients of heat loading
            d = 3061.331e0
            e = -48.810e0
            f = -78.559e0
            g = -291.820e0
            h = 0.267e0
            i = -0.610e0
            j = 33.497e0

        elif icool == 2:
            # large lake or reservoir as a cooling body
            # heat loading, MW/acre, based on estimations from US power plants
            heatload = 0.10e0
            # coefficients as per Webster et al. 1995:
            # wind function coefficients
            a = 1.04e0
            b = 1.05e0
            c = 0.0e0
            # fitted coefficients of heat loading
            d = 3876.843e0
            e = -49.071e0
            f = -295.246e0
            g = -327.935e0
            h = 0.260e0
            i = 10.528e0
            j = 40.188e0

        elif icool == 3:
            # stream or river as a cooling body
            # heat loading, MW/acre, based on estimations from US power plants
            heatload = 0.20e0
            # coefficients as per Gulliver et al. 1986:
            # wind function coefficients
            a = 2.96e0
            b = 0.64e0
            c = 0.0e0
            # fitted coefficients of heat loading
            d = 2565.009e0
            e = -43.636e0
            f = -93.834e0
            g = -203.767e0
            h = 0.257e0
            i = 2.408e0
            j = 20.596e0

        # Unfortunately, the source spreadsheet was from the US, so the fits for
        #   water body heating due to heat loading and the cooling wind functions
        #   are in non-metric units, hence the conversions required here.
        # Limitations: maximum wind speed of ~5 m/s; initial water_usage_variables.watertemp < 25 degC

        # convert water_usage_variables.windspeed to mph
        water_usage_variables.windspeedmph = (
            water_usage_variables.windspeed * 2.237e0
        )

        # convert heat loading into cal/(cm2.sec)
        heatloadimp = heatload * 1000000.0e0 * 0.239e0 / 40469000.0e0

        # estimate how heat loading will raise temperature, for this water body
        heatratio = (
            d
            + (e * water_usage_variables.watertemp)
            + (f * water_usage_variables.windspeedmph)
            + (g * heatload)
            + (h * water_usage_variables.watertemp**2)
            + (i * water_usage_variables.windspeedmph**2)
            + (j * heatload**2)
        )

        # estimate resultant heated water temperature
        water_usage_variables.watertempheated = water_usage_variables.watertemp + (
            heatloadimp * heatratio
        )

        # find wind function, m/(day.kPa), applicable to this water body:
        windfunction = (
            a
            + (b * water_usage_variables.windspeed)
            + (c * water_usage_variables.windspeed**2)
        ) / 1000.0e0

        # difference in saturation vapour pressure (Clausius-Clapeyron approximation)
        satvapdelta = (
            0.611e0
            * np.exp(
                (17.27e0 * water_usage_variables.watertempheated)
                / (237.3e0 + water_usage_variables.watertempheated)
            )
        ) - (
            0.611e0
            * np.exp(
                (17.27e0 * water_usage_variables.watertemp)
                / (237.3e0 + water_usage_variables.watertemp)
            )
        )

        # find 'forced evaporation' driven by heat inserted into system
        deltae = (
            water_usage_variables.waterdens
            * water_usage_variables.latentheat
            * windfunction
            * satvapdelta
        )

        # convert heat loading to J/(m2.day)
        heatloadmet = heatload * 1000000.0e0 / 4046.85642e0 * SECDAY

        # find evaporation ratio: ratio of the heat used to evaporate water
        #   to the total heat discharged through the tower
        water_usage_variables.evapratio = deltae / heatloadmet
        # Diehl et al. USGS Report 2013-5188, http://dx.doi.org/10.3133/sir20135188

        water_usage_variables.volheat = (
            water_usage_variables.waterdens * water_usage_variables.latentheat
        )

        water_usage_variables.energypervol = (
            water_usage_variables.volheat / water_usage_variables.evapratio
        )

        water_usage_variables.volperenergy = (
            1.0e0 / water_usage_variables.energypervol * 1000000.0e0
        )

        water_usage_variables.evapvol = (
            wastetherm * water_usage_variables.volperenergy
        )

        # using this method the estimates for pond, lake and river evaporation produce similar results,
        #   the average will be taken and used in the next stage of calculation
        evapsum = evapsum + water_usage_variables.evapvol

    evapsum = evapsum / icool

    # water volume withdrawn from external source depends on recirculation or 'once-through' system choice
    #   Estimated as a ratio to evaporated water (averaged across observed dataset)
    #   as per Diehl et al. USGS Report 2014-5184, http://dx.doi.org/10.3133/sir20145184

    # recirculating water system:
    water_usage_variables.wateruserecirc = 1.0e0 * evapsum

    # once-through water system:
    water_usage_variables.wateruseonethru = 98.0e0 * evapsum

    # end break

    #  Output section
    if output:
        po.ovarre(
            self.outfile,
            "Volume used in recirculating water system (m3/day)",
            "(wateruserecirc)",
            water_usage_variables.wateruserecirc,
            "OP ",
        )
        po.ovarre(
            self.outfile,
            "Volume used in once-through water system (m3/day)",
            "(wateruseonethru)",
            water_usage_variables.wateruseonethru,
            "OP ",
        )