Description: "Package with correlations for cooling tower performance"

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## Buildings.Fluid.HeatExchangers.CoolingTowers.Correlations

Package with correlations for cooling tower performance

### Information

This package contains the performance curve for the Buildings.Fluid.HeatExchangers.CoolingTowers.YorkCalc cooling tower model.

Extends from Modelica.Icons.MaterialProperty (Icon for property classes).

### Package Content

Name | Description
--- | ---
yorkCalc | Cooling tower performance correlation for YorkCalc model
BoundsYorkCalc | Coefficient data record for properties of York cooling tower model
Examples | Collection of models that illustrate model use and test models
BaseClasses | Package with base classes for Buildings.Fluid.HeatExchangers.CoolingTowers.Correlations

## Buildings.Fluid.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.

### Inputs

Type | Name | Default | Description
--- | --- | --- | ---
Temperature | TWetBul |  | Air wet-bulb inlet temperature [K]
MassFraction | FRWat |  | Ratio actual over design water mass flow ratio [1]
MassFraction | FRAir |  | Ratio actual over design air mass flow ratio [1]
Nominal condition
TemperatureDifference | TRan |  | Range temperature (water in - water out) [K]

### Outputs

Type | Name | Description
--- | --- | ---
TemperatureDifference | TApp | Approach temperature [K]

### Modelica definition

function yorkCalc "Cooling tower performance correlation for YorkCalc model" input Modelica.SIunits.TemperatureDifference TRan "Range temperature (water in - water out)"; input Modelica.SIunits.Temperature TWetBul "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.TemperatureDifference TApp "Approach temperature"; protected Modelica.SIunits.Conversions.NonSIunits.Temperature_degC TWetBul_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 TWetBul_degC :=Modelica.SIunits.Conversions.to_degC(TWetBul); // smoothMax is added to the numerator and denominator so that // liqGasRat -> 1, as both FRWat -> 0 and FRAir -> 0 liqGasRat := Buildings.Utilities.Math.Functions.smoothMax(x1=1E-4, x2=FRWat, deltaX=1E-5)/ Buildings.Utilities.Math.Functions.smoothMax(x1=1E-4, x2=FRAir, deltaX=1E-5); TApp := c[1] + c[2] * TWetBul_degC + c[3] * TWetBul_degC * TWetBul_degC + c[4] * TRan + c[5] * TWetBul_degC * TRan + c[6] * TWetBul_degC * TWetBul_degC * TRan + c[7] * TRan * TRan + c[8] * TWetBul_degC * TRan * TRan + c[9] * TWetBul_degC * TWetBul_degC * TRan * TRan + c[10] * liqGasRat + c[11] * TWetBul_degC * liqGasRat + c[12] * TWetBul_degC * TWetBul_degC * liqGasRat + c[13] * TRan * liqGasRat + c[14] * TWetBul_degC * TRan * liqGasRat + c[15] * TWetBul_degC * TWetBul_degC * TRan * liqGasRat + c[16] * TRan * TRan * liqGasRat + c[17] * TWetBul_degC * TRan * TRan * liqGasRat + c[18] * TWetBul_degC * TWetBul_degC * TRan * TRan * liqGasRat + c[19] * liqGasRat * liqGasRat + c[20] * TWetBul_degC * liqGasRat * liqGasRat + c[21] * TWetBul_degC * TWetBul_degC * liqGasRat * liqGasRat + c[22] * TRan * liqGasRat * liqGasRat + c[23] * TWetBul_degC * TRan * liqGasRat * liqGasRat + c[24] * TWetBul_degC * TWetBul_degC * TRan * liqGasRat * liqGasRat + c[25] * TRan * TRan * liqGasRat * liqGasRat + c[26] * TWetBul_degC * TRan * TRan * liqGasRat * liqGasRat + c[27] * TWetBul_degC * TWetBul_degC * TRan * TRan * liqGasRat * liqGasRat; end yorkCalc;

## Buildings.Fluid.HeatExchangers.CoolingTowers.Correlations.BoundsYorkCalc

Coefficient data record for properties of York cooling tower model

### Information

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

Extends from Buildings.Fluid.HeatExchangers.CoolingTowers.Correlations.BaseClasses.Bounds (Coefficient data record for properties of cooling tower model).

### Parameters

Type | Name | Default | Description
--- | --- | --- | ---
Temperature | TAirInWB_min | 273.15 - 34.4 | Minimum air inlet wet bulb temperature [K]
Temperature | TAirInWB_max | 273.15 + 26.7 | Maximum air inlet wet bulb temperature [K]
Temperature | TRan_min | 1.1 | Minimum range temperature [K]
Temperature | TRan_max | 22.2 | Minimum range temperature [K]
Temperature | TApp_min | 1.1 | Minimum approach temperature [K]
Temperature | TApp_max | 40 | Minimum approach temperature [K]
Real | FRWat_min | 0.75 | Minimum water flow ratio
Real | FRWat_max | 1.25 | Maximum water flow ratio
Real | liqGasRat_max | 8 | Maximum liquid to gas ratio

### Modelica definition

record BoundsYorkCalc "Coefficient data record for properties of York cooling tower model" extends Buildings.Fluid.HeatExchangers.CoolingTowers.Correlations.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;