Natural Cooling Tower CapabilityCalculations in PMAX

Frank ToddPSEG

Greg AlderSCIENTECH

PPMMAAXX CCooooll iinngg TToowweerrMMooddeell

z Cooling Tower at Hope Creek– Hope Creek is a 3293 Mwt

Boiling Water Reactor– Natural Draft Counter Flow

Tower– Rejects 2176 Mwt– Operates at a Range of 25°F.– Circ Water flow: 552,000 gpm

Fill

Drift Eliminators

Air Flow

Wet Bulb

RelativeHumidity

Water flowfromcondenser

" Cooling Tower CapabilityCalculation IAW Cooling TowerInstitute Code Test.

" Use Performance Method forNatural Draft Cooling Tower

" Determine predicted flow basedon vendor curves and ratio withactual flow

Q = (Test gpm/predicted gpm) X100

" Variables for curves:

" Range

" Relative Humidity

" Wet bulb Temperature

" Outlet (Cold) WaterTemperature

" Predicted flow rate

TOWER CAPABILITY (Q)Run date 09/06/98Run time 1530-1630

Inputs are in BLUEWet bulb temperature deg F 70.34Dry bulb temperature deg F 87.28 84.9 414,000 SUMX 264.5Barometric pressure psia 14.681 88.1 552,000 SUMY 1656000Relative humidity % 43.46 (preferably from CTI disk) 91.5 690,000 SUMXY ###

SUMXX 23333.78Circ water temp deg F 92.87 SLOPE 41479.39Circ water flow rate (test) gpm 612,249 Y INT ###Circ water flow rate (test) lbm/hr 304,841,590Circ water enthalpy Btu/lbm 60.9

Make-up water temp deg F 86.77Make-up water flow rate gpm 48,000Make-up water flow rate lbm/hr 23,925,688Make-up water enthalpy Btu/lbm 54.8

Inlet (hot) water temperature deg F 117.77Outlet (cold) water temperature deg F 93.35Range deg F 24.4

Predicted Circ Water Flow gpm 767,759Tower Capability (Q) % 79.74

Circ water flow rate (spec) gpm 414,000 552,000 690,000Predicted outlet water temp deg F 84.9 88.1 91.5

Hope Creek Cooling Tower Capability Test

84.5 85.0 85.5 86.0 86.5 87.0 87.5 88.0 88.5 89.0 89.5 90.0 90.5 91.0 91.5 92.0

400,000

425,000

450,000

475,000

500,000

525,000

550,000

575,000

600,000

625,000

650,000

675,000

700,000

Column 11

Cold Water Temperature

Flowgpm

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z Use data from met tower and plantz Perform corrections to dataz Input data to excel spreadsheetz Spreadsheet uses logical functions

to solve the four variables.z Capability is calculatedz Target Cold Water temperature is

calculatedz Lost Mwe due to cooling tower

inefficiencies

WWhhyy IInntteeggrraattee CCooooll iinngg TToowweerrMMooddeell iinnttoo PPMMAAXX??

z Give operations ability to detectproblems with the cooling towerand possibly correct them.

z Ability to trend more dataz Help prevent "wild goose chase"

for Mwez Remove the "hunch factor" from

how the plant should operateunder various conditions.

MMooddeell iinngg AApppprrooaacchh

z PMAX and PEPSE provideunivariate and bivariate curves

z Linear interpolationz Solution requires four inputs to

obtain the tower capability

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z WB = wet bulb temperature(Deg F)

z RH = relative humidity (%)z RANGE = tower water delta T

(Deg F)z FLOW = circ water flow (GPM)

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15 RANGE – 414000 FLOW23 RANGE – 414000 FLOW29 RANGE – 414000 FLOW15 RANGE – 512000 FLOW23 RANGE – 512000 FLOW29 RANGE – 512000 FLOW15 RANGE – 690000 FLOW23 RANGE – 690000 FLOW29 RANGE – 690000 FLOW

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Sample: RANGE between 15 to23°F

Y15 + [(Y23 – Y15)/(23-15)]/(RANGE – 15)

LLooggiiccaall SStteeppss

15-23 RANGE – 414000 FLOW23-29 RANGE – 414000 FLOW15-23 RANGE – 512000 FLOW23-29 RANGE – 512000 FLOW15-23 RANGE – 690000 FLOW23-29 RANGE – 690000 FLOW

Use same output variable for eachflow set.

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Sample: RANGE between414000 - 512000

Y414000 + [(Y512000 –Y414000)/(512000-414000)]/(FLOW – 414000)

LLooggiiccaall SStteeppss

414000 – 512000 FLOW512000 – 690000 FLOW

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z Effectively modeled 3+ inputcurves for linear interpolation

z Future modifications– Predicted circ water temperature– Mwe effect