Buildings.Media.Specialized.Air.PerfectGas
Model for air as a perfect gas
Information
This package contains a thermally perfect model of moist air.
A medium is called thermally perfect if
- it is in thermodynamic equilibrium,
- it is chemically not reacting, and
- internal energy and enthalpy are functions of temperature only.
In addition, this medium model is calorically perfect, i.e., the specific heat capacities at constant pressure cp and constant volume cv are both constant (Bower 1998).
This medium uses the ideal gas law
ρ = p ⁄(R T),
where ρ is the density, p is the pressure, R is the gas constant and T is the temperature.
The enthalpy is computed using the convention that h=0 if T=0 °C and no water vapor is present.
Note that for typical building simulations, the media Buildings.Media.Air should be used as it leads generally to faster simulation.
References
Bower, William B. A primer in fluid mechanics: Dynamics of flows in one space dimension. CRC Press. 1998.
Extends from Modelica.Media.Interfaces.PartialCondensingGases (Base class for mixtures of condensing and non-condensing gases), Modelica.Icons.Package (Icon for standard packages).
Package Content
Name | Description |
---|---|
Water=1 | Index of water (in substanceNames, massFractions X, etc.) |
Air=2 | Index of air (in substanceNames, massFractions X, etc.) |
ThermodynamicState | ThermodynamicState record for moist air |
BaseProperties | |
Xsaturation | Steam water mass fraction of saturation boundary in kg_water/kg_moistair |
setState_pTX | Thermodynamic state as function of p, T and composition X |
setState_phX | Thermodynamic state as function of p, h and composition X |
setState_dTX | Thermodynamic state as function of d, T and composition X |
gasConstant | Gas constant |
saturationPressureLiquid | Return saturation pressure of water as a function of temperature T in the range of 273.16 to 373.16 K |
saturationPressureLiquid_der | Time derivative of saturationPressureLiquid |
sublimationPressureIce | Saturation curve valid for 223.16 <= T <= 273.16. Outside of these limits a (less accurate) result is returned |
sublimationPressureIce_der | Derivative function for 'sublimationPressureIce' |
saturationPressure | Saturation curve valid for 223.16 <= T <= 373.16 (and slightly outside with less accuracy) |
pressure | Gas pressure |
temperature | Gas temperature |
density | Gas density |
specificEntropy | Specific entropy (liquid part neglected, mixing entropy included) |
enthalpyOfVaporization | Enthalpy of vaporization of water |
HeatCapacityOfWater | Specific heat capacity of water (liquid only) which is constant |
enthalpyOfLiquid | Enthalpy of liquid (per unit mass of liquid) which is linear in the temperature |
der_enthalpyOfLiquid | Temperature derivative of enthalpy of liquid per unit mass of liquid |
enthalpyOfCondensingGas | Enthalpy of steam per unit mass of steam |
der_enthalpyOfCondensingGas | Derivative of enthalpy of steam per unit mass of steam |
enthalpyOfNonCondensingGas | Enthalpy of non-condensing gas per unit mass of steam |
der_enthalpyOfNonCondensingGas | Derivative of enthalpy of non-condensing gas per unit mass of steam |
enthalpyOfGas | Enthalpy of gas mixture per unit mass of gas mixture |
enthalpyOfDryAir | Enthalpy of dry air per unit mass of dry air |
der_enthalpyOfDryAir | Derivative of enthalpy of dry air per unit mass of dry air |
specificHeatCapacityCp | Specific heat capacity of gas mixture at constant pressure |
der_specificHeatCapacityCp | Derivative of specific heat capacity of gas mixture at constant pressure |
specificHeatCapacityCv | Specific heat capacity of gas mixture at constant volume |
der_specificHeatCapacityCv | Derivative of specific heat capacity of gas mixture at constant volume |
dynamicViscosity | dynamic viscosity of dry air |
thermalConductivity | Thermal conductivity of dry air as a polynomial in the temperature |
specificEnthalpy | Specific enthalpy |
specificEnthalpy_pTX | Specific enthalpy |
specificInternalEnergy | Specific internal energy |
specificGibbsEnergy | Specific Gibbs energy |
specificHelmholtzEnergy | Specific Helmholtz energy |
temperature_phX | Compute temperature from specific enthalpy and mass fraction |
GasProperties | Coefficient data record for properties of perfect gases |
dryair | Dry air properties |
steam | Steam properties |
k_mair=steam.MM/dryair.MM | Ratio of molar weights |
h_fg=Buildings.Utilities.Psychrometrics.Constants.h_fg | Latent heat of evaporation of water |
cpWatLiq=Buildings.Utilities.Psychrometrics.Constants.cpWatLiq | Specific heat capacity of liquid water |
s_pTX | Return specific entropy of moist air as a function of pressure p, temperature T and composition X (only valid for phi<1) |
s_pTX_der | Return specific entropy of moist air as a function of pressure p, temperature T and composition X (only valid for phi<1) |
Inherited | |
fluidConstants={Modelica.Media.IdealGases.Common.FluidData.H2O,Modelica.Media.IdealGases.Common.FluidData.N2} | Constant data for the fluid |
moleToMassFractions | Return mass fractions X from mole fractions |
massToMoleFractions | Return mole fractions from mass fractions X |
ThermoStates=Modelica.Media.Interfaces.Choices.IndependentVariables.pTX | Enumeration type for independent variables |
mediumName="Moist air unsaturated perfect gas" | Name of the medium |
substanceNames={"water","air"} | 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=false | = 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=273.15 | Reference temperature of Medium: default 25 deg Celsius |
reference_X={0.01,0.99} | 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 |
setState_psX | Return thermodynamic state as function of p, s and composition X or Xi |
setSmoothState | Return thermodynamic state so that it smoothly approximates: if x > 0 then state_a else state_b |
prandtlNumber | Return the Prandtl number |
heatCapacity_cp | Alias for deprecated name |
heatCapacity_cv | Alias for deprecated name |
isentropicExponent | Return isentropic exponent |
isentropicEnthalpy | Return isentropic enthalpy |
velocityOfSound | Return velocity of sound |
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 |
density_phX | Return density from p, h, 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 Integer Water=1 "Index of water (in substanceNames, massFractions X, etc.)";
constant Integer Air=2 "Index of air (in substanceNames, massFractions X, etc.)";
constant GasProperties dryair( R = Modelica.Media.IdealGases.Common.SingleGasesData.Air.R, MM = Modelica.Media.IdealGases.Common.SingleGasesData.Air.MM, cp = Buildings.Utilities.Psychrometrics.Constants.cpAir, cv = Buildings.Utilities.Psychrometrics.Constants.cpAir -Modelica.Media.IdealGases.Common.SingleGasesData.Air.R) "Dry air properties";
constant GasProperties steam( R = Modelica.Media.IdealGases.Common.SingleGasesData.H2O.R, MM = Modelica.Media.IdealGases.Common.SingleGasesData.H2O.MM, cp = Buildings.Utilities.Psychrometrics.Constants.cpSte, cv = Buildings.Utilities.Psychrometrics.Constants.cpSte -Modelica.Media.IdealGases.Common.SingleGasesData.H2O.R) "Steam properties";
constant Real k_mair = steam.MM/dryair.MM "Ratio of molar weights";
constant Modelica.SIunits.SpecificEnergy h_fg= Buildings.Utilities.Psychrometrics.Constants.h_fg "Latent heat of evaporation of water";
constant Modelica.SIunits.SpecificHeatCapacity cpWatLiq= Buildings.Utilities.Psychrometrics.Constants.cpWatLiq "Specific heat capacity of liquid water";
Buildings.Media.Specialized.Air.PerfectGas.ThermodynamicState
ThermodynamicState record for moist air
Information
Extends from (Thermodynamic state variables).
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.BaseProperties
Information
Extends from (Base properties (p, d, T, h, u, R, MM and, if applicable, X and Xi) of a medium).
Parameters
Type | Name | Default | Description |
---|---|---|---|
Boolean | standardOrderComponents | true | If true, and reducedX = true, the last element of X will be computed from the other ones |
Advanced | |||
Boolean | preferredMediumStates | false | = true if StateSelect.prefer shall be used for the independent property variables of the medium |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.Xsaturation
Steam water mass fraction of saturation boundary in kg_water/kg_moistair
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
MassFraction | X_sat | Steam mass fraction of sat. boundary [kg/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.setState_pTX
Thermodynamic state as function of p, T and composition X
Information
Extends from Modelica.Media.Air.MoistAir.setState_pTX (Return thermodynamic state as function of pressure p, temperature T and composition X).
Inputs
Type | Name | Default | Description |
---|---|---|---|
AbsolutePressure | p | Pressure [Pa] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | reference_X | Mass fractions [kg/kg] |
Outputs
Type | Name | Description |
---|---|---|
ThermodynamicState | state | Thermodynamic state |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.setState_phX
Thermodynamic state as function of p, h and composition X
Information
Function to set the state for given pressure, enthalpy and species concentration.Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
AbsolutePressure | p | Pressure [Pa] | |
SpecificEnthalpy | h | Specific enthalpy [J/kg] | |
MassFraction | X[:] | Mass fractions [kg/kg] |
Outputs
Type | Name | Description |
---|---|---|
ThermodynamicState | state |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.setState_dTX
Thermodynamic state as function of d, T and composition X
Information
The thermodynamic state record is computed from density d, temperature T and composition X.Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Density | d | Density [kg/m3] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | reference_X | Mass fractions [kg/kg] |
Outputs
Type | Name | Description |
---|---|---|
ThermodynamicState | state | Thermodynamic state |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.gasConstant
Gas constant
Information
Extends from (Return the gas constant of the mixture (also for liquids)).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state |
Outputs
Type | Name | Description |
---|---|---|
SpecificHeatCapacity | R | Mixture gas constant [J/(kg.K)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.saturationPressureLiquid
Return saturation pressure of water as a function of temperature T in the range of 273.16 to 373.16 K
Information
Saturation pressure of water above the triple point temperature is computed from temperature. It's range of validity is between 273.16 and 373.16 K. Outside these limits a less accurate result is returned.Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | saturation temperature [K] |
Outputs
Type | Name | Description |
---|---|---|
AbsolutePressure | psat | saturation pressure [Pa] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.saturationPressureLiquid_der
Time derivative of saturationPressureLiquid
Information
Derivative function of Buildings.Media.Specialized.Air.PerfectGas.saturationPressureLiquidExtends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | Saturation temperature [K] | |
Real | dTsat | dTsat( unit... | Saturation temperature derivative [K/s] |
Outputs
Type | Name | Description |
---|---|---|
Real | psat_der | Saturation pressure [Pa/s] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.sublimationPressureIce
Saturation curve valid for 223.16 <= T <= 273.16. Outside of these limits a (less accurate) result is returned
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | Sublimation temperature [K] |
Outputs
Type | Name | Description |
---|---|---|
AbsolutePressure | psat | Sublimation pressure [Pa] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.sublimationPressureIce_der
Derivative function for 'sublimationPressureIce'
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | Sublimation temperature [K] | |
Real | dTsat | Sublimation temperature derivative [K/s] |
Outputs
Type | Name | Description |
---|---|---|
Real | psat_der | Sublimation pressure derivative [Pa/s] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.saturationPressure
Saturation curve valid for 223.16 <= T <= 373.16 (and slightly outside with less accuracy)
Information
Extends from (Return saturation pressure of condensing fluid).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | Tsat | Saturation temperature [K] |
Outputs
Type | Name | Description |
---|---|---|
AbsolutePressure | psat | Saturation pressure [Pa] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.pressure
Gas pressure
Information
Pressure is returned from the thermodynamic state record input as a simple assignment.Extends from (Return pressure).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
AbsolutePressure | p | Pressure [Pa] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.temperature
Gas temperature
Information
Temperature is returned from the thermodynamic state record input as a simple assignment.Extends from (Return temperature).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
Temperature | T | Temperature [K] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.density
Gas density
Information
Density is computed from pressure, temperature and composition in the thermodynamic state record applying the ideal gas law.Extends from (Return density).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
Density | d | Density [kg/m3] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.specificEntropy
Specific entropy (liquid part neglected, mixing entropy included)
Information
Specific entropy is calculated from the thermodynamic state record, assuming ideal gas behavior and including entropy of mixing. Liquid or solid water is not taken into account, the entire water content X[1] is assumed to be in the vapor state (relative humidity below 1.0).Extends from (Return specific entropy).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
SpecificEntropy | s | Specific entropy [J/(kg.K)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.enthalpyOfVaporization
Enthalpy of vaporization of water
Information
Extends from (Return vaporization enthalpy of condensing fluid).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | Temperature [K] |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnthalpy | r0 | Vaporization enthalpy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.HeatCapacityOfWater
Specific heat capacity of water (liquid only) which is constant
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | [K] |
Outputs
Type | Name | Description |
---|---|---|
SpecificHeatCapacity | cp_fl | [J/(kg.K)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.enthalpyOfLiquid
Enthalpy of liquid (per unit mass of liquid) which is linear in the temperature
Information
Extends from (Return liquid enthalpy of condensing fluid).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | Temperature [K] |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | Liquid enthalpy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.der_enthalpyOfLiquid
Temperature derivative of enthalpy of liquid per unit mass of liquid
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
Real | der_T | temperature derivative |
Outputs
Type | Name | Description |
---|---|---|
Real | der_h | derivative of liquid enthalpy |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.enthalpyOfCondensingGas
Enthalpy of steam per unit mass of steam
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | steam enthalpy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.der_enthalpyOfCondensingGas
Derivative of enthalpy of steam per unit mass of steam
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
Real | der_T | temperature derivative |
Outputs
Type | Name | Description |
---|---|---|
Real | der_h | derivative of steam enthalpy |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.enthalpyOfNonCondensingGas
Enthalpy of non-condensing gas per unit mass of steam
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | enthalpy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.der_enthalpyOfNonCondensingGas
Derivative of enthalpy of non-condensing gas per unit mass of steam
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
Real | der_T | temperature derivative |
Outputs
Type | Name | Description |
---|---|---|
Real | der_h | derivative of steam enthalpy |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.enthalpyOfGas
Enthalpy of gas mixture per unit mass of gas mixture
Information
Extends from (Return enthalpy of non-condensing gas mixture).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | Temperature [K] | |
MassFraction | X[:] | Vector of mass fractions [kg/kg] |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | Specific enthalpy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.enthalpyOfDryAir
Enthalpy of dry air per unit mass of dry air
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | dry air enthalpy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.der_enthalpyOfDryAir
Derivative of enthalpy of dry air per unit mass of dry air
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Temperature | T | temperature [K] | |
Real | der_T | temperature derivative |
Outputs
Type | Name | Description |
---|---|---|
Real | der_h | derivative of dry air enthalpy |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.specificHeatCapacityCp
Specific heat capacity of gas mixture at constant pressure
Information
Extends from (Return specific heat capacity at constant pressure).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
SpecificHeatCapacity | cp | Specific heat capacity at constant pressure [J/(kg.K)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.der_specificHeatCapacityCp
Derivative of specific heat capacity of gas mixture at constant pressure
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | ||
ThermodynamicState | der_state |
Outputs
Type | Name | Description |
---|---|---|
Real | der_cp | [J/(kg.K.s)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.specificHeatCapacityCv
Specific heat capacity of gas mixture at constant volume
Information
Extends from (Return specific heat capacity at constant volume).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
SpecificHeatCapacity | cv | Specific heat capacity at constant volume [J/(kg.K)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.der_specificHeatCapacityCv
Derivative of specific heat capacity of gas mixture at constant volume
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | ||
ThermodynamicState | der_state |
Outputs
Type | Name | Description |
---|---|---|
Real | der_cv | [J/(kg.K.s)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.dynamicViscosity
dynamic viscosity of dry air
Information
Extends from (Return dynamic viscosity).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
DynamicViscosity | eta | Dynamic viscosity [Pa.s] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.thermalConductivity
Thermal conductivity of dry air as a polynomial in the temperature
Information
Extends from (Return thermal conductivity).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
ThermalConductivity | lambda | Thermal conductivity [W/(m.K)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.specificEnthalpy
Specific enthalpy
Information
Extends from (Return specific enthalpy).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | Specific enthalpy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.specificEnthalpy_pTX
Specific enthalpy
Information
Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
Pressure | p | Pressure [Pa] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | Mass fractions of moist air [1] |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnthalpy | h | Specific enthalpy at p, T, X [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.specificInternalEnergy
Specific internal energy
Information
Extends from Modelica.Icons.Function (Icon for functions), (Return specific internal energy).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnergy | u | Specific internal energy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.specificGibbsEnergy
Specific Gibbs energy
Information
Extends from Modelica.Icons.Function (Icon for functions), (Return specific Gibbs energy).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnergy | g | Specific Gibbs energy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.specificHelmholtzEnergy
Specific Helmholtz energy
Information
Extends from Modelica.Icons.Function (Icon for functions), (Return specific Helmholtz energy).
Inputs
Type | Name | Default | Description |
---|---|---|---|
ThermodynamicState | state | Thermodynamic state record |
Outputs
Type | Name | Description |
---|---|---|
SpecificEnergy | f | Specific Helmholtz energy [J/kg] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.temperature_phX
Compute temperature from specific enthalpy and mass fraction
Information
Temperature as a function of specific enthalpy and species concentration. The pressure is input for compatibility with the medium models, but the temperature is independent of the pressure.Extends from Modelica.Icons.Function (Icon for functions).
Inputs
Type | Name | Default | Description |
---|---|---|---|
AbsolutePressure | p | Pressure [Pa] | |
SpecificEnthalpy | h | specific enthalpy [J/kg] | |
MassFraction | X[:] | mass fractions of composition [kg/kg] |
Outputs
Type | Name | Description |
---|---|---|
Temperature | T | temperature [K] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.GasProperties
Coefficient data record for properties of perfect gases
Information
This data record contains the coefficients for perfect gases.
Extends from Modelica.Icons.Record (Icon for records).
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.s_pTX
Return specific entropy of moist air as a function of pressure p, temperature T and composition X (only valid for phi<1)
Inputs
Type | Name | Default | Description |
---|---|---|---|
Pressure | p | Pressure [Pa] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | Mass fractions of moist air [1] |
Outputs
Type | Name | Description |
---|---|---|
SpecificEntropy | s | Specific entropy at p, T, X [J/(kg.K)] |
Modelica definition
Buildings.Media.Specialized.Air.PerfectGas.s_pTX_der
Return specific entropy of moist air as a function of pressure p, temperature T and composition X (only valid for phi<1)
Inputs
Type | Name | Default | Description |
---|---|---|---|
Pressure | p | Pressure [Pa] | |
Temperature | T | Temperature [K] | |
MassFraction | X[:] | Mass fractions of moist air [1] | |
Real | dp | Derivative of pressure [Pa/s] | |
Real | dT | Derivative of temperature [K/s] | |
Real | dX[nX] | Derivative of mass fractions [1/s] |
Outputs
Type | Name | Description |
---|---|---|
Real | ds | Specific entropy at p, T, X [J/(kg.K.s)] |