Contents - Index

Fluid Property Information


EES provides built-in thermophysical property data for the fluids listed below.  The fluids are grouped into Real Fluids, Ideal Gases, and Brines.   Property data for air-water mixtures (psychrometrics) are provided by fluid AirH2O.  Incompressible substances are not listed as they are provided with external Lookup table files.  However, you can view a list of all incompressible substances by selecting Function Info from the Options window, clicking the Thermophysical properties button and then selecting the Incompressible option. 


Click on a fluid name to access additional information for that fluid.  All names in EES are case-insensitive.  Note that, in addition to the list of fluids shown below, the property functions will operate with any of the 1262 gases provided in the NASA ideal gas data baseAdditional fluid property data can be added by the user.   


------------------------------------------------------------- REAL FLUIDS ----------------------------------------------- 

Acetone MDM R11 R290

Air_ha MD4M R12 R365mfc

Ammonia MM R13 R404A

Argon m-Xylene R13I1 R407C

Benzene Methane R14 R410A

Butene Methanol R22 R423A

Carbondioxide o-Xylene R23 R500

Carbonmonoxide n-Butane R32 R502

CarbonylSulfide n-Decane R40 R507A

Cis-2-Butene n-Dodecane R41 R508B

Cyclohexane n-Heptane R113 R600

Cyclopentane n-Hexane R114 R600a

D4 n-Octane R115 R717

D5 n-Nonane R116 R718

Deuterium   n-Pentane R123 R744

DeuteriumOxide n-Undecane R124 RC318

DiethylEther Neon R125 R1216

DimethylCarbonate Neopentane R134a R1225ye(Z)

DimethylEther Nitrogen R141b R1233zd(E)

Ethane NitrousOxide R142b R1234yf

Ethanol Novec649 R143a R1234ze(E)

Ethylbenzene orthoHydrogen R143m R1234ze(Z)

Ethylene Oxygen R152a R1243zf

Fluorine o-Zylene R161 RE245cb2

Helium paraHydrogen R218 RE245fa2

HFE7000 Propane R227ea  

HFE7200 p-Xylene R236ea  

HFE7500 Propylene R236fa

HFO1336mzz(Z) SES36 R245fa

Hydrogen Steam     

HydrogenChloride Steam_IAPWS

HydrogenSulfide Steam_NBS

Ice SulfurDioxide                                 --------- MIXTURES ---------

Isobutane SulfurHexafluoride                                           NH3H2O

Isobutene Toluene

Isohexane trans-2-butene

Isopentane Water

Krypton Xenon



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

Air CACL2   (Calcium Chloride-Water)                           Incompressible substances are provided in

AirH2O EA  (Ethylene Alcohol-Water)                                   separate Lookup (.LKT) tables.   See the 

Ar EG  (Ethylene Glycol-Water)                                    Function Information dialog for a

CH3OH GLYC  (Glycerol-Water)                                           list of these substances. 

CH4 K2CO3  (Potassium Carbonate-Water)    

C2H2 KAC  (Potassium Acetate-Water)

C2H4 KFO  (Potassium Formate-Water)

C2H6 LICL  (Lithium Chloride-Water)

C2H5OH MA  (Methyl Alcohol-Water)

C3H8 MGCL2  (Magnesium Chloride-Water)

C4H10 NACL  (Sodium Chloride-Water)

C5H12 NH3W  (Ammonia-Water)

C6H14 PG  (Propylene Glycol-Water)












NASA Gases  



The fluid properties are of three distinct types:  ideal gas, real fluid 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 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.  Otherwise, the fluid properties in the subcooled region are determined using the Martin-Hou equation of state (A.I.Ch.E. Journal, Vol. 1, No. 2, 1955, pp. 142-151) and by assuming 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.


The property keywords Water, Steam, Steam_NBS and R718 are treated identically.  All four keywords provided access to property correlations published by Harr, Gallagher, and Kell (Hemisphere, 1984).  These property correlations are accurate and were the basis of the international standard for water before 1995. Steam_IAPWS provides the most accurate property data for water substance and it is the current international standard.  Steam_IAPWS is available in the Professional version.