Buildings.HeatExchangers.CoolingTowers.Correlations

Package with correlations for cooling tower performance

Package Content

NameDescription
Buildings.HeatExchangers.CoolingTowers.Correlations.BaseClasses BaseClasses Package with base classes for mathematical functions
Buildings.HeatExchangers.CoolingTowers.Correlations.BoundsYorkCalc BoundsYorkCalc Coefficient data record for properties of perfect gases
Buildings.HeatExchangers.CoolingTowers.Correlations.Examples Examples Collection of models that illustrate model use and test models
Buildings.HeatExchangers.CoolingTowers.Correlations.yorkCalc yorkCalc Cooling tower performance correlation for YorkCalc model


Buildings.HeatExchangers.CoolingTowers.Correlations.BoundsYorkCalc Buildings.HeatExchangers.CoolingTowers.Correlations.BoundsYorkCalc

Coefficient data record for properties of perfect gases

Information


This data record contains the bounds for the YorkCalc cooling tower correlations.


Parameters

TypeNameDefaultDescription
TemperatureTAirInWB_min273.15 - 34.4Minimum air inlet wet bulb temperature [K]
TemperatureTAirInWB_max273.15 + 26.7Maximum air inlet wet bulb temperature [K]
TemperatureTRan_min1.1Minimum range temperature [K]
TemperatureTRan_max22.2Minimum range temperature [K]
TemperatureTApp_min1.1Minimum approach temperature [K]
TemperatureTApp_max40Minimum approach temperature [K]
MassFractionFRWat_min0.75Minimum water flow ratio [1]
MassFractionFRWat_max1.25Maximum water flow ratio [1]
MassFractionliqGasRat_max8Maximum liquid to gas ratio [1]

Modelica definition

record BoundsYorkCalc 
  "Coefficient data record for properties of perfect gases" 
  extends BaseClasses.Bounds(TAirInWB_min = 273.15-34.4,
  TAirInWB_max = 273.15+26.7,
  TRan_min =     1.1,
  TRan_max =     22.2,
  TApp_min =     1.1,
  TApp_max =     40,
  FRWat_min =     0.75,
  FRWat_max =    1.25,
  liqGasRat_max = 8);
  
end BoundsYorkCalc;

Buildings.HeatExchangers.CoolingTowers.Correlations.yorkCalc

Cooling tower performance correlation for YorkCalc model

Information


Correlation for approach temperature for YorkCalc cooling tower model. See Examples/YorkCalc.mo for the graph.


Parameters

TypeNameDefaultDescription
Nominal condition
TemperatureTRan Range temperature (water in - water out) [K]

Inputs

TypeNameDefaultDescription
TemperatureTWB Air wet-bulb inlet temperature [K]
MassFractionFRWat Ratio actual over design water mass flow ratio [1]
MassFractionFRAir Ratio actual over design air mass flow ratio [1]
Nominal condition
TemperatureTRan Range temperature (water in - water out) [K]

Outputs

TypeNameDescription
TemperatureTAppApproach temperature [K]

Modelica definition

function yorkCalc 
  "Cooling tower performance correlation for YorkCalc model" 
  annotation(derivative=BaseClasses.der_yorkCalc);  
  
  
  input Modelica.SIunits.Temperature TRan 
    "Range temperature (water in - water out)";
  input Modelica.SIunits.Temperature TWB "Air wet-bulb inlet temperature";
  input Modelica.SIunits.MassFraction FRWat 
    "Ratio actual over design water mass flow ratio";
  input Modelica.SIunits.MassFraction FRAir 
    "Ratio actual over design air mass flow ratio";
  
  output Modelica.SIunits.Temperature TApp "Approach temperature";
  
protected 
  Modelica.SIunits.CelsiusTemperature TWB_degC "Air wet-bulb inlet temperature";
  Modelica.SIunits.MassFraction liqGasRat "Liquid to gas mass flow ratio";
  constant Real c[:] = {-0.359741205, -0.055053608,  0.0023850432,
                      0.173926877, -0.0248473764,  0.00048430224,
                      -0.005589849456,  0.0005770079712, -0.00001342427256,
                      2.84765801111111, -0.121765149,  0.0014599242,
                      1.680428651, -0.0166920786, -0.0007190532,
                     -0.025485194448,  0.0000487491696,  0.00002719234152,
                     -0.0653766255555556, -0.002278167,  0.0002500254,
                     -0.0910565458,  0.00318176316,  0.000038621772,
                     -0.0034285382352,  0.00000856589904, -0.000001516821552} 
    "Polynomial coefficients";
  
algorithm 
  TWB_degC :=Modelica.SIunits.Conversions.to_degC(TWB);
  liqGasRat := FRWat/FRAir;
  TApp := c[1] +
       c[2] * TWB_degC +
       c[3] * TWB_degC * TWB_degC +
       c[4] * TRan +
       c[5] * TWB_degC * TRan +
       c[6] * TWB_degC * TWB_degC * TRan +
       c[7] * TRan * TRan +
       c[8] * TWB_degC * TRan * TRan +
       c[9] * TWB_degC * TWB_degC * TRan * TRan +
       c[10] * liqGasRat +
       c[11] * TWB_degC * liqGasRat +
       c[12] * TWB_degC * TWB_degC * liqGasRat +
       c[13] * TRan * liqGasRat +
       c[14] * TWB_degC * TRan * liqGasRat +
       c[15] * TWB_degC * TWB_degC * TRan * liqGasRat +
       c[16] * TRan * TRan * liqGasRat +
       c[17] * TWB_degC * TRan * TRan * liqGasRat +
       c[18] * TWB_degC * TWB_degC * TRan * TRan * liqGasRat +
       c[19] * liqGasRat * liqGasRat +
       c[20] * TWB_degC * liqGasRat * liqGasRat +
       c[21] * TWB_degC * TWB_degC * liqGasRat * liqGasRat +
       c[22] * TRan * liqGasRat * liqGasRat +
       c[23] * TWB_degC * TRan * liqGasRat * liqGasRat +
       c[24] * TWB_degC * TWB_degC * TRan * liqGasRat * liqGasRat +
       c[25] * TRan * TRan * liqGasRat * liqGasRat +
       c[26] * TWB_degC * TRan * TRan * liqGasRat * liqGasRat +
       c[27] * TWB_degC * TWB_degC * TRan * TRan * liqGasRat * liqGasRat;
end yorkCalc;

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