Buildings.Media.Antifreeze.PropyleneGlycolWater

Package with model for propylene glycol - water with constant properties

Information

This medium package models propylene glycol - water mixtures.

The mass density, specific heat capacity, thermal conductivity and viscosity are assumed constant and evaluated at a set temperature and mass fraction of propylene glycol within the mixture. The dependence of the four properties are shown on the figure below.

The accuracy of the thermophysical properties is dependent on the temperature variations encountered during simulations. The figure below shows the relative error of the the four properties over a 10 °C range around the temperature used to evaluate the constant properties. The maximum errors are 0.8 % for mass density, 1.5 % for specific heat capacity, 3.2 % for thermal conductivity and 250 % for dynamic viscosity.

The figure below shows the relative error of the the four properties over a 20 °C range around the temperature used to evaluate the constant proepties. The maximum errors are 1.6 % for mass density, 3.0 % for specific heat capacity, 6.2 % for thermal conductivity and 950 % for dynamic viscosity.

The enthalpy is computed using the convention that h=0 if T=0 °C.

Limitations

Density, specific heat capacity, thermal conductivity and viscosity are constant. The propylene glycol/water mixture is modeled as an incompressible liquid. There are no phase changes. The medium is limited to temperatures below 100 °C and mass fractions below 0.60. As is the case for Buildings.Media.Water, this medium package should not be used if the simulation relies on the dynamic viscosity.

Typical use and important parameters

The temperature and mass fraction must be specified for the evaluation of the constant thermophysical properties. A typical use of the package is (e.g. for a temperature of 20 °C and a mass fraction of 0.40):

Medium = Buildings.Media.Antifreeze.PropyleneGlycolWater(property_T=293.15, X_a=0.40)

Extends from Modelica.Media.Interfaces.PartialSimpleMedium (Medium model with linear dependency of u, h from temperature. All other quantities, especially density, are constant.).

Package Content

Name	Description
property_T	Temperature for evaluation of constant fluid properties
X_a	Mass fraction of propylene glycol in water
BaseProperties	Base properties
X_a_min=0.	Minimum allowed mass fraction of propylene glycol in water
X_a_max=0.6	Maximum allowed mass fraction of propylene glycol in water
simplePropyleneGlycolWaterConstants
proCoe	Coefficients for evaluation of thermo-physical properties
density_TX_a	Evaluate density of antifreeze-water mixture
dynamicViscosity_TX_a	Evaluate dynamic viscosity of antifreeze-water mixture
fusionTemperature_TX_a	Evaluate temperature of fusion of antifreeze-water mixture
polynomialProperty	Evaluates thermophysical property from 2-variable polynomial
specificHeatCapacityCp_TX_a	Evaluate specific heat capacity of antifreeze-water mixture
thermalConductivity_TX_a	Evaluate thermal conductivity of antifreeze-water mixture
Inherited
cp_const=specificHeatCapacityCp_TX_a(T=property_T, X_a=X_a)	Constant specific heat capacity at constant pressure
cv_const=cp_const	Constant specific heat capacity at constant volume
d_const=density_TX_a(T=property_T, X_a=X_a)	Constant density
eta_const=dynamicViscosity_TX_a(T=property_T, X_a=X_a)	Constant dynamic viscosity
lambda_const=thermalConductivity_TX_a(T=property_T, X_a=X_a)	Constant thermal conductivity
a_const=1484	Constant velocity of sound
T_min=fusionTemperature_TX_a(T=property_T, X_a=X_a)	Minimum temperature valid for medium model
T_max=Modelica.SIunits.Conversions.from_degC(100)	Maximum temperature valid for medium model
T0=273.15	Zero enthalpy temperature
MM_const=(X_a/simplePropyleneGlycolWaterConstants[1].molarMass + (1 - X_a)/0.018015268)^(-1)	Molar mass
fluidConstants=simplePropyleneGlycolWaterConstants	Fluid constants
ThermodynamicState	Thermodynamic state
setState_pTX	Return thermodynamic state from p, T, and X or Xi
setState_phX	Return thermodynamic state from p, h, and X or Xi
setState_psX	Return thermodynamic state from p, s, and X or Xi
setState_dTX	Return thermodynamic state from d, T, and X or Xi
setSmoothState	Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b
dynamicViscosity	Return dynamic viscosity
thermalConductivity	Return thermal conductivity
pressure	Return pressure
temperature	Return temperature
density	Return density
specificEnthalpy	Return specific enthalpy
specificHeatCapacityCp	Return specific heat capacity at constant pressure
specificHeatCapacityCv	Return specific heat capacity at constant volume
isentropicExponent	Return isentropic exponent
velocityOfSound	Return velocity of sound
specificEnthalpy_pTX	Return specific enthalpy from p, T, and X or Xi
temperature_phX	Return temperature from p, h, and X or Xi
density_phX	Return density from p, h, and X or Xi
specificInternalEnergy	Return specific internal energy
specificEntropy	Return specific entropy
specificGibbsEnergy	Return specific Gibbs energy
specificHelmholtzEnergy	Return specific Helmholtz energy
isentropicEnthalpy	Return isentropic enthalpy
isobaricExpansionCoefficient	Returns overall the isobaric expansion coefficient beta
isothermalCompressibility	Returns overall the isothermal compressibility factor
density_derp_T	Returns the partial derivative of density with respect to pressure at constant temperature
density_derT_p	Returns the partial derivative of density with respect to temperature at constant pressure
density_derX	Returns the partial derivative of density with respect to mass fractions at constant pressure and temperature
molarMass	Return the molar mass of the medium
setState_pT	Return thermodynamic state from p and T
setState_ph	Return thermodynamic state from p and h
setState_ps	Return thermodynamic state from p and s
setState_dT	Return thermodynamic state from d and T
density_ph	Return density from p and h
temperature_ph	Return temperature from p and h
pressure_dT	Return pressure from d and T
specificEnthalpy_dT	Return specific enthalpy from d and T
specificEnthalpy_ps	Return specific enthalpy from p and s
temperature_ps	Return temperature from p and s
density_ps	Return density from p and s
specificEnthalpy_pT	Return specific enthalpy from p and T
density_pT	Return density from p and T
ThermoStates=Modelica.Media.Interfaces.Choices.IndependentVariables.pT	Enumeration type for independent variables
mediumName="PropyleneGlycolWater(X_a = " + String(X_a) + ", property_T = " + String(property_T) + ")"	Name of the medium
substanceNames={mediumName}	Names of the mixture substances. Set substanceNames={mediumName} if only one substance.
extraPropertiesNames=fill("", 0)	Names of the additional (extra) transported properties. Set extraPropertiesNames=fill("",0) if unused
singleState=true	= true, if u and d are not a function of pressure
reducedX=true	= true if medium contains the equation sum(X) = 1.0; set reducedX=true if only one substance (see docu for details)
fixedX=true	= true if medium contains the equation X = reference_X
reference_p=300000	Reference pressure of Medium: default 1 atmosphere
reference_T=273.15	Reference temperature of Medium: default 25 deg Celsius
reference_X={1}	Default mass fractions of medium
p_default=300000	Default value for pressure of medium (for initialization)
T_default=Modelica.SIunits.Conversions.from_degC(20)	Default value for temperature of medium (for initialization)
h_default=specificEnthalpy_pTX(p_default, T_default, X_default)	Default value for specific enthalpy of medium (for initialization)
X_default=reference_X	Default value for mass fractions of medium (for initialization)
C_default=fill(0, nC)	Default value for trace substances of medium (for initialization)
nS=size(substanceNames, 1)	Number of substances
nX=nS	Number of mass fractions
nXi=if fixedX then 0 else if reducedX then nS - 1 else nS	Number of structurally independent mass fractions (see docu for details)
nC=size(extraPropertiesNames, 1)	Number of extra (outside of standard mass-balance) transported properties
C_nominal=1.0e-6*ones(nC)	Default for the nominal values for the extra properties
FluidConstants	Critical, triple, molecular and other standard data of fluid
prandtlNumber	Return the Prandtl number
heatCapacity_cp	Alias for deprecated name
heatCapacity_cv	Alias for deprecated name
beta	Alias for isobaricExpansionCoefficient for user convenience
kappa	Alias of isothermalCompressibility for user convenience
density_derp_h	Return density derivative w.r.t. pressure at const specific enthalpy
density_derh_p	Return density derivative w.r.t. specific enthalpy at constant pressure
specificEntropy_pTX	Return specific enthalpy from p, T, and X or Xi
density_pTX	Return density from p, T, and X or Xi
temperature_psX	Return temperature from p,s, and X or Xi
density_psX	Return density from p, s, and X or Xi
specificEnthalpy_psX	Return specific enthalpy from p, s, and X or Xi
MassFlowRate	Type for mass flow rate with medium specific attributes
AbsolutePressure	Type for absolute pressure with medium specific attributes
Density	Type for density with medium specific attributes
DynamicViscosity	Type for dynamic viscosity with medium specific attributes
EnthalpyFlowRate	Type for enthalpy flow rate with medium specific attributes
MassFraction	Type for mass fraction with medium specific attributes
MoleFraction	Type for mole fraction with medium specific attributes
MolarMass	Type for molar mass with medium specific attributes
MolarVolume	Type for molar volume with medium specific attributes
IsentropicExponent	Type for isentropic exponent with medium specific attributes
SpecificEnergy	Type for specific energy with medium specific attributes
SpecificInternalEnergy	Type for specific internal energy with medium specific attributes
SpecificEnthalpy	Type for specific enthalpy with medium specific attributes
SpecificEntropy	Type for specific entropy with medium specific attributes
SpecificHeatCapacity	Type for specific heat capacity with medium specific attributes
SurfaceTension	Type for surface tension with medium specific attributes
Temperature	Type for temperature with medium specific attributes
ThermalConductivity	Type for thermal conductivity with medium specific attributes
PrandtlNumber	Type for Prandtl number with medium specific attributes
VelocityOfSound	Type for velocity of sound with medium specific attributes
ExtraProperty	Type for unspecified, mass-specific property transported by flow
CumulativeExtraProperty	Type for conserved integral of unspecified, mass specific property
ExtraPropertyFlowRate	Type for flow rate of unspecified, mass-specific property
IsobaricExpansionCoefficient	Type for isobaric expansion coefficient with medium specific attributes
DipoleMoment	Type for dipole moment with medium specific attributes
DerDensityByPressure	Type for partial derivative of density with respect to pressure with medium specific attributes
DerDensityByEnthalpy	Type for partial derivative of density with respect to enthalpy with medium specific attributes
DerEnthalpyByPressure	Type for partial derivative of enthalpy with respect to pressure with medium specific attributes
DerDensityByTemperature	Type for partial derivative of density with respect to temperature with medium specific attributes
DerTemperatureByPressure	Type for partial derivative of temperature with respect to pressure with medium specific attributes
SaturationProperties	Saturation properties of two phase medium
FluidLimits	Validity limits for fluid model
FixedPhase	Phase of the fluid: 1 for 1-phase, 2 for two-phase, 0 for not known, e.g., interactive use
Basic	The most basic version of a record used in several degrees of detail
IdealGas	The ideal gas version of a record used in several degrees of detail
TwoPhase	The two phase fluid version of a record used in several degrees of detail

Types and constants

  constant Modelica.SIunits.Temperature property_T
    "Temperature for evaluation of constant fluid properties";

  constant Modelica.SIunits.MassFraction X_a
    "Mass fraction of propylene glycol in water";

  constant Modelica.SIunits.MassFraction X_a_min=0.
    "Minimum allowed mass fraction of propylene glycol in water";

  constant Modelica.SIunits.MassFraction X_a_max=0.6
    "Maximum allowed mass fraction of propylene glycol in water";

  constant Modelica.Media.Interfaces.Types.Basic.FluidConstants[1]
    simplePropyleneGlycolWaterConstants(
    each chemicalFormula="C3H8O2",
    each structureFormula="CH3CH(OH)CH2OH",
    each casRegistryNumber="57-55-6",
    each iupacName="1,2-Propylene glycol",
    each molarMass=0.07609);

  constant Buildings.Media.Antifreeze.BaseClasses.PropertyCoefficients
    proCoe(
    X_a_ref=0.307031,
    T_ref=Modelica.SIunits.Conversions.from_degC(32.7083),
    nX_a=6,
    nT={4,4,4,3,2,1},
    nTot=18,
    a_d={1.018e3,-5.406e-1,-2.666e-3,1.347e-5,7.604e-1,-9.450e-3,5.541e-5,-1.343e-7,
        -2.498e-3,2.700e-5,-4.018e-7,3.376e-9,-1.550e-4,2.829e-6,-7.175e-9,-1.131e-6,
        -2.221e-8,2.342e-8},
    a_eta={6.837e-1,-3.045e-2,2.525e-4,-1.399e-6,3.328e-2,-3.984e-4,4.332e-6,-1.860e-8,
        5.453e-5,-8.600e-8,-1.593e-8,-4.465e-11,-3.900e-6,1.054e-7,-1.589e-9,-1.587e-8,
        4.475e-10,3.564e-9},
    a_Tf={-1.325e1,-3.820e-5,7.865e-7,-1.733e-9,-6.631e-1,6.774e-6,-6.242e-8,-7.819e-10,
        -1.094e-2,5.332e-8,-4.169e-9,3.288e-11,-2.283e-4,-1.131e-8,1.918e-10,-3.409e-6,
        8.035e-11,1.465e-8},
    a_cp={3.882e3,2.699e0,-1.659e-3,-1.032e-5,-1.304e1,5.070e-2,-4.752e-5,
        1.522e-6,-1.598e-1,9.534e-5,1.167e-5,-4.870e-8,3.539e-4,3.102e-5,-2.950e-7,
        5.000e-5,-7.135e-7,-4.959e-7},
    a_lambda={4.513e-1,7.955e-4,3.482e-8,-5.966e-9,-4.795e-3,-1.678e-5,8.941e-8,
        1.493e-10,2.076e-5,1.563e-7,-4.615e-9,9.897e-12,-9.083e-8,-2.518e-9,
        6.543e-11,-5.952e-10,-3.605e-11,2.104e-11})
    "Coefficients for evaluation of thermo-physical properties";

Buildings.Media.Antifreeze.PropyleneGlycolWater.BaseProperties

Base properties

Information

This base properties model is identical to Modelica.Media.Water.ConstantPropertyLiquidWater, except that the equation u = cv_const*(T - reference_T) has been replaced by u=h because cp_const=cv_const. Also, the model checks if the mass fraction of the mixture is within the allowed limits.

Parameters

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.density_TX_a

Evaluate density of antifreeze-water mixture

Information

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Outputs

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.dynamicViscosity_TX_a

Evaluate dynamic viscosity of antifreeze-water mixture

Information

Dynamic viscosity of antifreeze-water mixture at specified mass fraction and temperature, based on Melinder (2010).

References

Melinder, Åke. 2010. Properties of Secondary Working Fluids (Secondary Refrigerants or Coolants, Heat Transfer Fluids) for Indirect Systems. Paris: IIR/IIF.

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Outputs

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.fusionTemperature_TX_a

Evaluate temperature of fusion of antifreeze-water mixture

Information

Fusion temperature of antifreeze-water mixture at specified mass fraction and temperature, based on Melinder (2010).

References

Melinder, Åke. 2010. Properties of Secondary Working Fluids (Secondary Refrigerants or Coolants, Heat Transfer Fluids) for Indirect Systems. Paris: IIR/IIF.

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Outputs

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.polynomialProperty

Evaluates thermophysical property from 2-variable polynomial

Information

Evaluates a thermophysical property of a mixture, based on correlations proposed by Melinder (2010).

The polynomial has the form

f = a₁ (x-xm)⁰(y-ym)⁰ + a₂ (x-xm)⁰(y-ym)¹ + ... + a_ny[1] (x-xm)⁰(y-ym)^ny[1]-1 + ... + a_ny[1])+1 (x-xm)¹(y-ym)⁰ + ... + a_ny[1]+ny[2] (x-xm)¹(y-ym)^ny[2]-1 + ...

References

Melinder, Åke. 2010. Properties of Secondary Working Fluids (Secondary Refrigerants or Coolants, Heat Transfer Fluids) for Indirect Systems. Paris: IIR/IIF.

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Outputs

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.specificHeatCapacityCp_TX_a

Evaluate specific heat capacity of antifreeze-water mixture

Information

Specific heat capacity of antifreeze-water mixture at specified mass fraction and temperature, based on Melinder (2010).

References

Melinder, Åke. 2010. Properties of Secondary Working Fluids (Secondary Refrigerants or Coolants, Heat Transfer Fluids) for Indirect Systems. Paris: IIR/IIF.

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Outputs

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.thermalConductivity_TX_a

Evaluate thermal conductivity of antifreeze-water mixture

Information

Thermal conductivity of antifreeze-water mixture at specified mass fraction and temperature, based on Melinder (2010).

References

Melinder, Åke. 2010. Properties of Secondary Working Fluids (Secondary Refrigerants or Coolants, Heat Transfer Fluids) for Indirect Systems. Paris: IIR/IIF.

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Outputs

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.BaseProperties.InputAbsolutePressure

Pressure as input signal connector

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.BaseProperties.InputMassFraction

Mass fraction as input signal connector

Modelica definition

Buildings.Media.Antifreeze.PropyleneGlycolWater.BaseProperties.InputSpecificEnthalpy

Specific enthalpy as input signal connector

Modelica definition