.Buildings.Media.Steam .Buildings.Media.SteamThis medium package models water vapor (pure steam, region 2, quality=1).
Thermodynamic properties are calculated primarily in terms of pressure and temperature. For thermodynamic property functions, the IAPWS-IF97 formulations are adapted, and approximate relationships are provided for commonly used functions to improve computational efficiency and provide backward compatability.
Detailed functions from Modelica.Media.Water.WaterIF97_R2pT are generally used, except for Buildings.Media.Steam.specificEnthalpy and Buildings.Media.Steam.specificEntropy (both "forward" functions), as well as their "backward" inverse functions Buildings.Media.Steam.temperature_ph and Buildings.Media.Steam.temperature_ps, which are numerically consistent with the forward functions. The following modifications were made relative to the Modelica.Media.Water.WaterIF97_R2pT medium package:
T_max=130°C. This is suitable for real-world condensate
return and boiler feedwater systems, which are typically vented to the atmosphere
with steam contained via steam traps (thus, T_max=100°C for the
condensate or feedwater in properly functioning systems).This model is intended for first generation district heating systems and other steam heating processes involving low and medium pressure steam.
W. Wagner et al., “The IAPWS industrial formulation 1997 for the thermodynamic properties of water and steam,” J. Eng. Gas Turbines Power, vol. 122, no. 1, pp. 150–180, 2000.
Kathryn Hinkelman, Saranya Anbarasu, Michael Wetter, Antoine Gautier, Wangda Zuo. 2022. “A Fast and Accurate Modeling Approach for Water and Steam Thermodynamics with Practical Applications in District Heating System Simulation,” Energy, 254(A), pp. 124227. 10.1016/j.energy.2022.124227
Kathryn Hinkelman, Saranya Anbarasu, Michael Wetter, Antoine Gautier, Baptiste Ravache, Wangda Zuo 2022. “Towards Open-Source Modelica Models For Steam-Based District Heating Systems.” Proc. of the 1st International Workshop On Open Source Modelling And Simulation Of Energy Systems (OSMSES 2022), Aachen, German, April 4-5, 2022. 10.1109/OSMSES54027.2022.9769121
| Name | Description |
|---|---|
 ThermodynamicState | Thermodynamic state variables |
 BaseProperties | Base properties (p, d, T, h, u, R, MM) of water |
 density | Returns density |
 dynamicViscosity | Return dynamic viscosity |
 molarMass | Return the molar mass of the medium |
 pressure | Return pressure |
 saturationPressure | Return saturation pressure of condensing fluid |
 saturationTemperature | Return saturation temperature |
 specificEnthalpy | Returns specific enthalpy |
 specificEntropy | Return specific entropy |
 specificInternalEnergy | Return specific internal energy |
 specificHeatCapacityCp | Specific heat capacity at constant pressure |
 specificHeatCapacityCv | Specific heat capacity at constant volume |
 specificGibbsEnergy | Specific Gibbs energy |
 specificHelmholtzEnergy | Specific Helmholtz energy |
 setState_dTX | Return the thermodynamic state as function of d and T |
 setState_pTX | Return the thermodynamic state as function of p and T |
 setState_phX | Return the thermodynamic state as function of p and h |
 setState_psX | Return the thermodynamic state as function of p and s |
 temperature | Return temperature |
 thermalConductivity | Return thermal conductivity |
 density_derh_p | Density derivative by specific enthalpy |
 density_derp_h | Density derivative by pressure |
 isentropicExponent | Return isentropic exponent |
 isothermalCompressibility | Isothermal compressibility of water |
 isobaricExpansionCoefficient | Isobaric expansion coefficient of water |
 isentropicEnthalpy | Isentropic enthalpy |
pHat and THat
from absolute to Modelica.Units.SI.PressureDifference and
Modelica.Units.SI.TemperatureDifference to prevent min/max
assertion errors during initilization.
rho_pT, created and used new function extending
Modelica.Media.Water.IF97_Utilities.BaseIF97.Basic.g2 with an
annotation smoothOrder=2. This is to specifically pass on the
smoothOrder=2 annotion placed on rho_pT to
the g2 function.