Contents - Index

Fluid Property Information


EES provides built-in  property data for the fluids listed below. The fluids are grouped into Real Fluids, Ideal Gases,  Brines, Incompressible Substances, and Mixtures (modeled as pseudo-pure substances).   Property data for air-water mixtures (psychrometrics) are provided by fluid AirH2O.  Thermophysical property data for hundreds of materials are also available in the Incompressible Substances and NASA libraries.


------------------- REAL FLUIDS --------------------          ---------MIXTURES ----------

Acetone MDM R11 Air_ha  R500

Acetylene MD2M R12 NH3H2O  R502  

Ammonia MD4M R13   R404A R507A  

Argon MM R13I1   R407A* R508B  

Benzene Methane R14 R407C R512A  

Butene Methanol R22 R407H* R513A  

Carbondioxide n-Butane R23 R410A R513B*  

Carbonmonoxide n-Decane R32 R417A  R514A  

CarbonylSulfide n-Dodecane R40 R422D* R515A  

Chlorine n-Heptane R41 R423AR515B*  

Cis-2-Butene n-Hexane R113 R427A* R516A*  

Cyclohexane n-Octane R114 R428A*    

Cyclopentane n-Nonane R115 R438A*    

D4 n-Pentane R116 R448A    

D5  n-Undecane R123 R449A    

Deuterium Neon R124 R450A    

DeuteriumOxide Neopentane R125 R452A    

DiethylEther Nitrogen R134a R452B    

DimethylCarbonate NitrousOxide R141b  R453A*    

DimethylEther Novec649 R142b R454A    

Ethane o-Xylene R143a R454B    

Ethanol orthoHydrogen R143m R454C    

Ethylbenzene Oxygen R152a R455A*    

Ethylene o-Zylene R161 R456A*    

EthyleneOxide paraHydrogen R218 R457A*    

Fluorine p-Xylene R227ea R460A*    

Helium Potassium* R236ea R463A*    

HFE7000 Propane R236fa R466A    

Hydrogen Propylene R245fa R469A*    

HydrogenChloride PropyleneGlycol R290  R470A*    

HydrogenSulfide Propyne R365mfc  R470B*    

Ice SES36 R600    

Isobutane Sodium* R600a    

Isobutene Steam R717       

Isohexane Steam_IAPWS R718    

Isooctane Steam_NBS R744    

Isopentane SulfurDioxide R1123

Krypton SulfurHexafluoride R1216      

m-Xylene Toluene R1224yd(Z)      

 trans-2-butene R1225ye(Z)      

 Water R1233zd(E)       

 Xenon R1234yf      










FLD files*     *Professional license only




----- IDEAL GASES -----            ------ BRINES ------                         ------ INCOMPRESSIBLE ------

Air CACL2   (Calcium Chloride-Water)               The Function Information dialog displays the 

AirH2O EA  (Ethylene Alcohol-Water)                       materials in the Incompressible Substances.

Ar EG  (Ethylene Glycol-Water)                        library.

CH3OH GLYC  (Glycerol-Water)                               

CH4 K2CO3  (Potassium Carbonate-Water)         Specific heat, enthalpy and entropy data are 

C2H2 KAC  (Potassium Acetate-Water)                 available for condensed substances in the 

C2H4 KFO  (Potassium Formate-Water)                NASA database.

C2H6 LICL  (Lithium Chloride-Water)

C2H5OH MA  (Methyl Alcohol-Water)                         NASA_EES procedure

C3H8 MGCL2  (Magnesium Chloride-Water)

C4H10 NACL  (Sodium Chloride-Water)

C5H12 NH3W  (Ammonia-Water)

C6H14 PG  (Propylene Glycol-Water)

















NASA Gases



Liquid Metals library


The fluid properties are of three distinct types:  ideal gas, real fluid/mixtures and brines/incompressible.  The enthalpy and internal energy of ideal gas substances are dependent only upon temperature.  EES will not accept pressure, along with temperature, as an independent property input in the Enthalpy and IntEnergy functions for ideal gas substances.  A general rule is that substances having a name that is a chemical formula, e.g.,  N2 or CO2, are implemented to be ideal gases whereas real fluids use spelled-out names, e.g., Nitrogen and CarbonDioxide.  Air and AirH2O (psychrometric relations) are exceptions to this rule in that both are based on ideal gas behavior.  Whenever a chemical symbol notation (e.g., Ar, N2, CO2, CH4 etc.) is used, the substance is modeled as an ideal gas and the enthalpy and entropy values are based on JANAF table references.  The JANAF table reference for enthalpy is based on the elements having an enthalpy value of 0 at 298K (537R).  The entropy of these substances is based on the Third Law of Thermodynamics. 


Whenever the substance name is spelled out (e.g., Argon, Steam (or Water or R718), Nitrogen, R12, CarbonDioxide, Methane, etc.) the substance is modeled as a real fluid with subcooled, saturated, and superheated phases.  Most of the real fluids and mixtures in the table above employ a high accuracy equation of state that accurately provides property information at all conditions including the vicinity of the critical point and the subcooled region.  Specific references to the equation of state are provided for each fluid.  A few fluids use the Martin-Hou equation of state (A.I.Ch.E. Journal, Vol. 1, No. 2, 1955, pp. 142-151) and assume the fluid is incompressible.  The Martin-Hou equation of state has a claimed accuracy of 1% in specific volume for conditions at which the density is less than 1.5 * Critical density.   Thermodynamic properties at densities greater than 1.5 * critical density or in the vicinity of the critical point may be inaccurate with the Martin-Hou equation of state.


Brine properties are provided given the temperature and mass concentration in %.  


NH3H2O (ammonia-water) is a mixture.  It requires 3 independent properties. The property designators are the same as for pure fluids with the following two differences.  X designates mass fraction.  Q designates quality.


Starting with version 10.364, the property keywords Water, Steam, R718 and Steam_IAPWS are treated identically.  All four keywords provided access to property correlations use the Steam_IAPWS property correlations, which provide the most accurate property data for water substance and it is the current international standard.  Steam_NBS and Ice use the property correlations published by Harr, Gallagher, and Kell (Hemisphere, 1984).These property correlations were the basis of the international standard for water before 1995.


Starting with version 10.627, EES can read .FDL files used with the NIST REFPROP program, which extends the number of pure fluids for which EES can provide property information.