Buildings.Media.ConstantPropertyLiquidWater

Information

• It allows computing a compressibility of the medium. This helps breaking algebraic loops, but the system gets stiff. The compressibility is defined by the constant kappa_const. If kappa_const=0, then the density is constant. Otherwise, the density is

  ρ(p) = ρ(p0) ( 1 + κ_const (p-p₀))

  This equation is implemented in the base class Buildings.Media.Interfaces.PartialSimpleMedium.
• It implements the function that computes the specific internal energy.

Package Content

Name	Description
specificInternalEnergy	Return specific internal energy
Inherited
cp_const	Constant specific heat capacity at constant pressure
cv_const	Constant specific heat capacity at constant volume
d_const	Constant density
eta_const	Constant dynamic viscosity
lambda_const	Constant thermal conductivity
a_const	Constant velocity of sound
T_min	Minimum temperature valid for medium model
T_max	Maximum temperature valid for medium model
T0=reference_T	Zero enthalpy temperature
MM_const	Molar mass
fluidConstants	fluid constants
ThermodynamicState	Thermodynamic state
kappa_const=0	Compressibility factor at constant temperature
p0=3E5	Reference pressure for compressibility and default medium pressure
constantDensity=(kappa_const <= 1E-20)	Flag, true if density is modeled as a constant
BaseProperties
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
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	Enumeration type for independent variables
mediumName="unusablePartialMedium"	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, 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=false	= true if medium contains the equation X = reference_X
reference_p=101325	Reference pressure of Medium: default 1 atmosphere
reference_T=298.15	Reference temperature of Medium: default 25 deg Celsius
reference_X=fill(1/nX, nX)	Default mass fractions of medium
p_default=101325	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)
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
specificEntropy	Return specific entropy
specificGibbsEnergy	Return specific Gibbs energy
specificHelmholtzEnergy	Return specific Helmholtz energy
heatCapacity_cp	alias for deprecated name
heatCapacity_cv	alias for deprecated name
isentropicEnthalpy	Return isentropic enthalpy
isobaricExpansionCoefficient	Return overall the isobaric expansion coefficient beta
beta	alias for isobaricExpansionCoefficient for user convenience
isothermalCompressibility	Return overall the isothermal compressibility factor
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
density_derp_T	Return density derivative w.r.t. pressure at const temperature
density_derT_p	Return density derivative w.r.t. temperature at constant pressure
density_derX	Return density derivative w.r.t. mass fraction
molarMass	Return the molar mass of the medium
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
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
MassFlowRate	Type for mass 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 resect to pressure with medium specific attributes
DerDensityByEnthalpy	Type for partial derivative of density with resect to enthalpy with medium specific attributes
DerEnthalpyByPressure	Type for partial derivative of enthalpy with resect to pressure with medium specific attributes
DerDensityByTemperature	Type for partial derivative of density with resect to temperature with medium specific attributes
Choices	Types, constants to define menu choices

Buildings.Media.ConstantPropertyLiquidWater.specificInternalEnergy

Information

Inputs

Type	Name	Default	Description
ThermodynamicState	state		thermodynamic state record

Outputs

Type	Name	Description
SpecificEnergy	u	Specific internal energy [J/kg]

Modelica definition

redeclare replaceable function extends specificInternalEnergy 
  "Return specific internal energy"
algorithm 
  u := cv_const * (state.T-T0);
end specificInternalEnergy;