BasePropertiesBase properties (p, d, T, h, u, R, MM and, if applicable, X and Xi) of a medium 
This information is part of the Modelica Standard Library maintained by the Modelica Association.
Model BaseProperties is a model within package PartialMedium and contains the declarations of the minimum number of variables that every medium model is supposed to support. A specific medium inherits from model BaseProperties and provides the equations for the basic properties.
The BaseProperties model contains the following 7+nXi variables (nXi is the number of independent mass fractions defined in package PartialMedium):
Variable  Unit  Description 
T  K  temperature 
p  Pa  absolute pressure 
d  kg/m3  density 
h  J/kg  specific enthalpy 
u  J/kg  specific internal energy 
Xi[nXi]  kg/kg  independent mass fractions m_i/m 
R  J/kg.K  gas constant 
M  kg/mol  molar mass 
In order to implement an actual medium model, one can extend from this base model and add 5 equations that provide relations among these variables. Equations will also have to be added in order to set all the variables within the ThermodynamicState record state.
If standardOrderComponents=true, the full composition vector X[nX] is determined by the equations contained in this base class, depending on the independent mass fraction vector Xi[nXi].
Additional 2 + nXi equations will have to be provided when using the BaseProperties model, in order to fully specify the thermodynamic conditions. The input connector qualifier applied to p, h, and nXi indirectly declares the number of missing equations, permitting advanced equation balance checking by Modelica tools. Please note that this doesn't mean that the additional equations should be connection equations, nor that exactly those variables should be supplied, in order to complete the model. For further information, see the Modelica.Media User's guide, and Section 4.7 (Balanced Models) of the Modelica 3.0 specification.
preferredMediumStates 
Value: false Type: Boolean Description: = true if StateSelect.prefer shall be used for the independent property variables of the medium 

standardOrderComponents 
Value: true Type: Boolean Description: If true, and reducedX = true, the last element of X will be computed from the other ones 
p 
Type: InputAbsolutePressure Description: Absolute pressure of medium 


Xi 
Type: InputMassFraction[nXi] Description: Structurally independent mass fractions 

h 
Type: InputSpecificEnthalpy Description: Specific enthalpy of medium 
state 
Type: ThermodynamicState Description: Thermodynamic state record for optional functions 

Modelica.Fluid.Sources.BaseClasses Partial component source with one fluid connector 

Modelica.Fluid.Sources.BaseClasses Partial component source with one fluid connector 

Modelica.Fluid.Interfaces Lumped volume with mass and energy balance 

Modelica.Fluid.Interfaces Base class for distributed volume models 

Modelica.Media.Examples.Utilities Fixed volume associated with a port by the finite volume method 

Modelica.Media.Examples.Utilities Ideal pump that produces a constant mass flow rate from a large reservoir at fixed temperature and mass fraction 

Modelica.Media.Examples.Utilities Ambient pressure, temperature and mass fraction source 

Modelica.Media.Examples.Tests.Components Fixed volume associated with a port by the finite volume method 

Modelica.Media.Examples.Tests.Components Ideal pump that produces a constant mass flow rate from a large reservoir at fixed temperature and mass fraction 

Modelica.Media.Examples.Tests.Components Ambient pressure, temperature and mass fraction source 
Modelica.Media.Incompressible.TableBased Base properties of T dependent medium 

Modelica.Media.Interfaces.PartialPureSubstance 

Modelica.Media.Interfaces.TemplateMedium Base properties of medium 