High-Level API

Function Listing

• ABFLSHdll()
• ALLPROPS0dll()
• ALLPROPS1dll()
• ALLPROPSdll()
• ERRMSGdll()
• FLAGSdll()
• GETENUMdll()
• REFPROP1dll()
• REFPROP2dll()
• REFPROPdll()
• SETFLUIDSdll()
• SETMIXTUREdll()
• SETPATHdll()

Function Documentation

subroutine ABFLSHdll(ab, a, b, z, iFlag, T, P, D, Dl, Dv, x, y, q, e, h, s, Cv, Cp, w, ierr, herr, ab_length, herr_length)

General flash calculation that handles all inputs of T, P, D, h, e, s, and q.

Includes both blind flash calculations, and situations where the phase is known to be liquid, vapor, or 2-phase, and thus the calculation time will be much faster.

Many of the 2-phase flash routines can accept initial estimates to decrease calculation time and improve convergence. ABFLSH does not accept these, and ABFL2 or other routines will need to be called to use the initial estimates. These routines end in the letters FL2.

Notes:

• Cp and w are not defined for 2-phase states; the flag -9999980 is returned.
• Cv for 2-phase states is not calculated (use CV2PK); the flag -9999990 is returned.

Information on ab

Valid character codes for ab are:

• T - Temperature [K]
• P - Pressure [kPa]
• D - Density [mol/L or kg/m^3]
• E - Internal energy [J/mol or kJ/kg]
• H - Enthalpy [J/mol or kJ/kg]
• S - Entropy [J/mol-K or kJ/kg]
• Q - Quality [mol/mol or kJ/kg]

• For example, ‘PH’ indicates pressure and enthalpy inputs.
• For saturation properties, use codes of ‘TQ’ or ‘PQ’ for ab, and send b=1.
• The order of the letters does not matter, for example ‘DH’ = ‘HD’ for saturated vapor values and b=0 for saturated liquid values.

Information on iFlags

Three flags are currently allowed, and are sent combined in a three digit integer value. The digit on the right is the mass flag (iMass) defined below, the middle digit is the phase flag (kph), and the digit on the left specifies other flags (k).

• iMass: Molar or mass flag

  • 0 - All inputs and outputs are given on a mole basis.
  • 1 - All inputs and outputs are given on a mass basis.
  • 2 - All inputs and outputs are given on a mass basis except composition, which is given on a mole basis.

• kph: Phase flag (except for inputs of Q)

  • 0 - Unknown phase, the saturation routines will be called to determine the phase, which adds a substantial amount of time needed to calculate the properties.
  • 1 - State point is in the liquid phase, do not call saturation routine to determine state.
  • 2 - State point is in the vapor phase, do not call saturation routine to determine state.
  • 3 - State point is in the two-phase region.

• kr,kq: Other flags for inputs of quality and either temperature or pressure (kq flag)

  • 0 - Default
  • 1 - Quality on a molar basis (moles vapor/total moles) (default, the value of 1 is not necessarily needed).
  • 2 - Quality on a mass basis (mass vapor/total mass); for inputs of T and either h or e (kr flag)
  • 3 - Return lower density root.
  • 4 - Return higher density root.

Examples:

• 000 - Default - Phase of state is unknown, molar units will be used everywhere, higher density root will be returned.
• 002 - Use mass based properties for everything except composition.
• 011 - State is in the liquid, properties are mass based.
• 300 - Return the lower density root for TH or TE inputs.
• 200 - All inputs are on a mole basis, but quality is sent on a mass basis.

Parameters:

• ab [char ,in] :: Character string composed of two letters that indicate the input properties.
• a [double ,in] :: Value of the property identified by the first letter in ab
• b [double ,in] :: Value of the property identified by the second letter in ab
• z (20) [double ,in] :: Composition (array of mole fractions) For TQ and PQ inputs, send b=-99 for melting line states and b=-98 for sublimation line states.
• iFlag [int ,in] :: Multiple flags combined into one variable (see above)
• T [double ,out] :: Temperature [K]
• P [double ,out] :: Pressure [kPa]
• D [double ,out] :: Density [mol/L or kg/m^3]
• Dl [double ,out] :: Molar density of the liquid phase [mol/L or kg/m^3]
• Dv [double ,out] :: Molar density of the vapor phase [mol/L or kg/m^3]; if only one phase is present, Dl = Dv = D.
• x (20) [double ,out] :: Composition of the liquid phase (array of mole or mass fractions)
• y (20) [double ,out] :: Composition of the vapor phase (array of mole or mass fractions); if only one phase is present, x = y = z.
• q [double ,out] :: Vapor quality on a MOLAR basis (moles of vapor/total moles)
• e [double ,out] :: Overall internal energy [J/mol or kJ/kg]
• h [double ,out] :: Overall enthalpy [J/mol or kJ/kg]
• s [double ,out] :: Overall entropy [J/mol-K or kJ/kg-K]
• Cv [double ,out] :: Isochoric (constant D) heat capacity [J/mol-K or kJ/kg-K]
• Cp [double ,out] :: Isobaric (constant P) heat capacity [J/mol-K or kJ/kg-K]
• w [double ,out] :: Speed of sound [m/s]
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• ab_length [int ] :: length of variable ab (default: 2)
• herr_length [int ] :: length of variable herr (default: 255)

Flags :

q flags

q > 0 and q < 1:  indicates a 2-phase state q < 0:Subcooled (compressed) liquid q = 0:Saturated liquid q = 1:Saturated vapor q > 1:Superheated vapor q = -998:Subcooled liquid, but quality not defined (usually P > Pc) q = 998:Superheated vapor, but quality not defined (usually T > Tc) q = 999:Supercritical state (T>Tc and P>Pc)

subroutine ALLPROPS0dll(iIn, iOut, iFlag, T, D, z, Output, ierr, herr, herr_length)

Calculate any single phase property defined in the iOut array and return the values in the Output array. This routine should NOT be called for two-phase states!

The output array is not reset so that several passes can be made to fill in holes left by the previous pass (such as entries at different T, D, or z). The caller can zero out this array if so desired.

This routine is designed with the “superuser” in mind. It removes all string comparisons to approach the speed that could be obtained by calling the dedicated functions (such as THERM), but making it easy by allowing all inputs to be calculated with one routine. Since the units are not returned here, look in the ALLPROPS documentation under the molar column.

These values of iOut are defined in the COMMONS.INC file and are obtained by a call to GETENUM, as such for the enthalpy:

call GETENUM (0,'H',iEnum,ierr,herr)

To obtain the pure fluid value for some of the inputs, add 10000*ic (where ic is the component number) to the value of the enumerated value. The properties that can be used for this are given the bottom of the comments section in the ALLPROPS routine.

Parameters:

• iIn [int ,in] :: Number of properties to calculate.
• iOut (200) [int ,in] :: Array of enumerated values that identify the property to be calculated (see above)
• iFlag [int ,in] :: Not yet used.
• T [double ,in] :: Temperature [K]
• D [double ,in] :: Density [mol/L]
• z (20) [double ,in] :: Overall composition (array of mole fractions)
• Output (200) [double ,out] :: Values of the calculated properties.
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• herr_length [int ] :: length of variable herr (default: 255)

subroutine ALLPROPS1dll(hOut, iUnits, T, D, z, c, ierr, herr, hOut_length, herr_length)

Short version of subroutine ALLPROPS that eliminates the arrays but allows the calculation of only one property at a time. All inputs and outputs are described in the ALLPROPS routine.

Parameters:

• hOut [char ,in] :: Input string of properties to calculate (of any length). Inputs can be separated by spaces, commas, semicolons, or bars, but should not be mixed. For example, a proper string would be hOut=’T,P,D,H,E,S’, whereas an improperly defined string would be hOut=’T,P;D H|E,S’. Use of lower or upper case is not important. Some properties will return multiple values, for example, hOut=’F,Fc,XMOLE’ will return 12 properties for a four component system, these being F(1), F(2), F(3), F(4), Fc(1), Fc(2), etc. To retrieve the property of a single component, use, for example, hOut=’XMOLE(2),XMOLE(3)’
• iUnits [int ,in] :: See subroutine REFPROP for a complete description of the iUnits input value. A negative value for iUnits indicates that the input temperature is given in K and density in mol/dm^3, (Refprop default units), otherwise T and D will be converted first to K and mol/dm^3. Do not use the negative value for the iUnits parameter everywhere, only in this one situation.
• T [double ,in] :: Temperature, with units based on the value of iUnits.
• D [double ,in] :: Density, with units based on the value of iUnits.
• z (20) [double ,in] :: Composition on a mole or mass basis (array of size ncmax=20)
• c [double ,out] :: Output value (array of size 200 dimensioned as double precision). The number -9999970 will be returned when errors occur or no input was requested.
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• hOut_length [int ] :: length of variable hOut (default: 255)
• herr_length [int ] :: length of variable herr (default: 255)

subroutine ALLPROPSdll(hOut, iUnits, iMass, iFlag, T, D, z, Output, hUnits, iUCodeArray, ierr, herr, hOut_length, hUnitsArray_length, herr_length)

Calculate the single-phase properties identified in the hOut string at the temperature, density, and composition sent to the routine. Return the properties in mass or molar units depending on iUnits.

Warning

Do NOT call this routine for two-phase states, otherwise it will return metastable states if near but inside the phase boundary, and complete nonsense at other conditions. The value of q that is returned from the flash routines will indicate a two phase state by returning a value between 0 and 1. In such a situation, properties can only be calculated for the saturated liquid and vapor states. For example, when calling PHFLSH:

call PHFLSH (P,h,z,T,D,Dl,Dv,x,y,q,e,s,Cv,Cp,w,ierr,herr)

If q>0 and q<1, then values of the liquid and vapor compositions will be returned in the x and y arrays, and the properties of the liquid and vapor states can be calculated, for example:

call ENTRO (T,Dl,x,sliq)
call ENTRO (T,Dv,x,svap)

ALLPROPS was the name of a program developed at the University of Idaho under the direction of R.B. Stewart and R.T Jacobsen at the Center for Applied Thermodynamic Studies (CATS), with S.G. Penoncello and S.W. Beyerlein as professors at this institution. The software was distributed for about 10 years until around 2000 when it was officially replaced by the Refprop program. Some of the techniques from ALLPROPS was used in the development of Version 6 of Refprop, and were in some ways its forerunner. The original code was DOS based and distributed on 3 1/2” floppy disks by regular mail. A Visual Basic version of ALLPROPS was developed in about 1995, and, although rarely distributed, inspired the graphical interface included with Version 7.0 and above of Refprop.

The ALLPROPS code was used to develop equations of state at the University of Idaho, and many of these are still in use today, such as ethanol, neon, R-11, R-12, R-22, R-23, R-143a, and the mixture air, along with the architecture behind the GERG-2008 mixture model. The equations of state for ethylene, nitrogen, and oxygen were developed in conjunction with the Ruhr University in Bochum, Germany, including a six month stay by R. Span from Bochum with E.W. Lemmon at Idaho while both worked on their upper degrees. The underlying code in the fitting program developed at CATS is still in use today, and has been used in nearly all equations of state developed over the last 20 years.

The name ALLPROPS was revived at NIST in 2017 in memory of the old but not forgotten program whose roots still form the foundation of much that goes on behind the scenes in the development of equations of state and property software.

Calling from the DLL

Two routines are available in the DLL, these are ALLPROPSdll and ALLPRP200dll. Both compress the hUnitsArray array so that it can be passed back as a single string. The segments are divided by the character ‘|’. Both routines use the same list of arguments:

(hOut,iUnits,iMass,iFlag,T,D,z,Output,hUnits,iUCode,ierr,herr)

In ALLPROPSdll, the hOut string is 255 characters long, the hUnits string is 1000 characters long, and the Output and iUCode arrays each have a length of 20. In ALLPRP200dll, the hOut and hUnits strings are 10000 characters long, and the Output and iUCode arrays each have a length of 200.

Below are the labels that can be sent in the hOut string and a very short description of the property and units based on either a SI molar system (iUnits=1) or SI mass system (iUnits=2, or 3 with temperature in C).

Note about criticals: The items TC,PC,DC will return the critical point of a pure fluid, or, when SATSPLN has been called, the critical point of the mixture (or a very close approximation). When the splines have not been set up, the values are the same as TCEST below. For the critical points of the pure fluids in a mixture, use TCRIT, etc., explained below, which is useful when multiple fluids have been loaded. Parameters in the HMX.BNC file, which, for a binary mixture, are close for Type I mixtures, but for a multi-component or non-Type I mixture, can be significantly wrong.

Label	Description	SI Molar Units	SI Mass Units
Regular properties
T	Temperature	[K]	[K]
P	Pressure	[kPa]	[kPa]
D	Density	[mol/dm^3]	[kg/m^3]
V	Volume	[dm^3/mol]	[m^3/kg]
E	Internal energy	[J/mol]	[kJ/kg]
H	Enthalpy	[J/mol]	[kJ/kg]
S	Entropy	[J/(mol*K)]	[(kJ/kg)/K]
CV	Isochoric heat capacity	[J/(mol*K)]	[(kJ/kg)/K]
CP	Isobaric heat capacity	[J/(mol*K)]	[(kJ/kg)/K]
CP/CV	Heat capacity ratio	[-]	[-]
W	Speed of sound	[m/s]	[m/s]
Z	Compressibility factor	[-]	[-]
JT	Isenthalpic Joule-Thomson coefficient	[K/kPa]	[K/kPa]
A	Helmholtz energy	[J/mol]	[kJ/kg]
G	Gibbs energy	[J/mol]	[kJ/kg]
R	Gas constant	[J/(mol*K)]	[(kJ/kg)/K]
M	Molar mass (or of the mixture)	[g/mol]	[g/mol]
QMASS	Quality (not implemented, q not known)	N.A.	[kg/kg]
QMOLE	Quality (not implemented, q not known)	[mol/mol]	N.A.
Not so regular properties
KAPPA	Isothermal compressibility	[1/kPa]	[1/kPa]
BETA	Volume expansivity	[1/K]	[1/K]
ISENK	Isentropic expansion coefficient	[-]	[-]
KT	Isothermal expansion coefficient	[-]	[-]
BETAS	Adiabatic compressibility	[1/kPa]	[1/kPa]
BS	Adiabatic bulk modulus	[kPa]	[kPa]
KKT	Isothermal bulk modulus	[kPa]	[kPa]
THROTT	Isothermal throttling coefficient	[dm^3/mol]	[m^3/kg]
Derivatives
DPDD	dP/dD at constant T	[kPa/(dm^3/mol)]	[kPa/(m^3/kg)]
DPDT	dP/dT at constant D	[kPa/K]	[kPa/K]
DDDP	dD/dP at constant T	[(mol/dm^3)/kPa]	[(kg/m^3)/kPa]
DDDT	dD/dT at constant P	[(mol/dm^3)/K]	[(kg/m^3)/K]
DTDP	dT/dP at constant D	[K/kPa]	[K/kPa]
DTDD	dT/dD at constant P	[(dm^3/mol)*K]	[(m^3/kg)*K]
D2PDD2	d^2P/dD^2 at constant T	[kPa/(dm^3/mol)^2]	[kPa/(m^3/kg)^2]
D2PDT2	d^2P/dT^2 at constant D	[kPa/K^2]	[kPa/K^2]
D2PDTD	d^2P/dTdD	[kPa/(dm^3/mol)/K]	[kPa/(m^3/kg)/K]
D2DDP2	d^2D/dP^2 at constant T	[(mol/dm^3)/kPa^2]	[(kg/m^3)/kPa^2]
D2DDT2	d^2D/dT^2 at constant P	[(mol/dm^3)/K^2]	[(kg/m^3)/K^2]
D2DDPT	d^2D/dPdT	[(mol/dm^3)/(kPa*K)]	[(kg/m^3)/[kPa*K]]
D2TDP2	d^2T/dP^2 at constant D	[K/kPa^2]	[K/kPa^2]
D2TDD2	d^2T/dD^2 at constant P	[(dm^3/mol)^2*K]	[(m^3/kg)^2*K]
D2TDPD	d^2T/dPdD	[K/(dm^3/mol)/kPa]	[K/(m^3/kg)/kPa]
Enthalpy derivatives
DHDT_D	dH/dT at constant D	[(J/mol)/K]	[(kJ/kg)/K]
DHDT_P	dH/dT at constant P	[(J/mol)/K]	[(kJ/kg)/K]
DHDD_P	dH/dD at constant P	[(J/mol)*(dm^3/mol)]	[(kJ/kg)*(m^3/kg)]
DHDD_T	dH/dD at constant T	[(J/mol)*(dm^3/mol)]	[(kJ/kg)*(m^3/kg)]
DHDP_T	dH/dP at constant T	[(J/mol)/kPa]	[(kJ/kg)/kPa]
DHDP_D	dH/dP at constant D	[(J/mol)/kPa]	[(kJ/kg)/kPa]
Entropy derivatives
DSDT_D	dS/dT at constant D	[(J/mol)/K^2]	[(kJ/kg)/K^2]
DSDT_P	dS/dT at constant P	[(J/mol)/K^2]	[(kJ/kg)/K^2]
DSDD_T	dS/dD at constant T	[(J/mol)*(dm^3/mol)/K]	[(kJ/kg)*(m^3/kg)/K]
DSDD_P	dS/dD at constant P	[(J/mol)*(dm^3/mol)/K]	[(kJ/kg)*(m^3/kg)/K]
DSDP_T	dS/dP at constant T	[(J/mol)/(kPa*K)]	[(kJ/kg)/[kPa*K]]
DSDP_D	dS/dP at constant D	[(J/mol)/(kPa*K)]	[(kJ/kg)/[kPa*K]]
Virial Coefficients
Bvir	Second virial coefficient	[dm^3/mol]	[m^3/kg]
Cvir	Third virial coefficient	[(dm^3/mol)^2]	[(m^3/kg)^2]
Dvir	Fourth virial coefficient	[(dm^3/mol)^3]	[(m^3/kg)^3]
Evir	Fifth virial coefficient	[(dm^3/mol)^4]	[(m^3/kg)^4]
dBvirdT	1st derivative of B with respect to T	[(dm^3/mol)/K]	[(m^3/kg)/K]
d2BvirdT2	2nd derivative of B with respect to T	[(dm^3/mol)/K^2]	[(m^3/kg)/K^2]
dCvirdT	1st derivative of C with respect to T	[(dm^3/mol)^2/K]	[(m^3/kg)^2/K]
d2CvirdT2	2nd derivative of C with respect to T	[(dm^3/mol)^2/K^2]	[(m^3/kg)^2/K^2]
dDvirdT	1st derivative of D with respect to T	[(dm^3/mol)^3/K]	[(m^3/kg)^3/K]
d2DvirdT2	2nd derivative of D with respect to T	[(dm^3/mol)^3/K^2]	[(m^3/kg)^3/K^2]
BA	Second acoustic virial coefficient	[dm^3/mol]	[m^3/kg]
CA	Third acoustic virial coefficient	[(dm^3/mol)^2]	[(m^3/kg)^2]
EOS testing properties
GRUN	Gruneisen parameter	[-]	[-]
PIP	Phase identification parameter	[-]	[-]
RIEM	Thermodyn. curvature (nm^3/molecule)
(Z-1)/D	(Z-1) over the density	[dm^3/mol]	[m^3/kg]
(Z-1)/P	(Z-1) over the pressure	[1/kPa]	[1/kPa]
P*V	Pressure times volume	[(dm^3/mol)*kPa]	[(m^3/kg)*kPa]
S*D	Entropy times density	[J/(mol*K)*(mol/dm^3)]	[(kJ/kg)*(kg/m^3)/K]
N1/T	Negative reciprocal temperature	[1/K]	[1/K]
RD	Rectilinear diameter (Dl+Dv)/2	[mol/dm^3]	[kg/m^3]
Properties from ancillary equations
ANC-TP	Vapor pressure from ancillary given T	[kPa]	[kPa]
ANC-TDL	Sat. liquid dens. from ancillary given T	[mol/dm^3]	[kg/m^3]
ANC-TDV	Sat. vapor dens. from ancillary given T	[mol/dm^3]	[kg/m^3]
ANC-PT	Vapor temp. from ancillary given P	[K]	[K]
ANC-DT	Vapor temp. from ancillary given D	[K]	[K]
MELT-TP	Melting pressure given T	[kPa]	[kPa]
MELT-PT	Melting temperature given P	[K]	[K]
SUBL-TP	Sublimation pressure given T	[kPa]	[kPa]
SUBL-PT	Sublimation temperature given P	[K]	[K]
Less common saturation properties
CSAT	Saturated heat capacity	[J/(mol*K)]	[(kJ/kg)/K]
CV2P	Isochoric two-phase heat capacity	[J/(mol*K)]	[(kJ/kg)/K]
DPDTSAT	dP/dT along the saturation line	[kPa/K]	[kPa/K]
DHDZSAT	dH/dZ along the sat. line (Waring)	[J/mol]	[kJ/kg]
LIQSPNDL	Density at the liquid spinodal	[mol/dm^3]	[kg/m^3]
VAPSPNDL	Density at the vapor spinodal	[mol/dm^3]	[kg/m^3]
Excess properties
VE	Excess volume	[dm^3/mol]	[m^3/kg]
EE	Excess energy	[J/mol]	[kJ/kg]
HE	Excess enthalpy	[J/mol]	[kJ/kg]
SE	Excess entropy	[J/(mol*K)]	[(kJ/kg)/K]
AE	Excess Helmholtz energy	[J/mol]	[kJ/kg]
GE	Excess Gibbs energy	[J/mol]	[kJ/kg]
B12	B12	[dm^3/mol]	[m^3/kg]
Ideal gas properties
P0	Ideal gas pressure	[kPa]	[kPa]
E0	Ideal gas internal energy	[J/mol]	[kJ/kg]
H0	Ideal gas enthalpy	[J/mol]	[kJ/kg]
S0	Ideal gas entropy	[J/(mol*K)]	[(kJ/kg)/K]
CV0	Ideal gas isochoric heat capacity	[J/(mol*K)]	[(kJ/kg)/K]
CP0	Ideal gas isobaric heat capacity	[J/(mol*K)]	[(kJ/kg)/K]
CP0/CV0	Ideal gas heat capacity ratio	[-]	[-]
W0	Ideal gas speed of sound	[m/s]	[m/s]
A0	Ideal gas Helmholtz energy	[J/mol]	[kJ/kg]
G0	Ideal gas Gibbs energy	[J/mol]	[kJ/kg]
P-P0	Pressure minus ideal gas pressure	[kPa]	[kPa]
Residual properties
PR	Residual pressure (P-D*Rxgas*T)	[kPa]	[kPa]
ER	Residual internal energy	[J/mol]	[kJ/kg]
HR	Residual enthalpy	[J/mol]	[kJ/kg]
SR	Residual entropy	[J/(mol*K)]	[(kJ/kg)/K]
CVR	Residual isochoric heat capacity	[J/(mol*K)]	[(kJ/kg)/K]
CPR	Residual isobaric heat capacity	[J/(mol*K)]	[(kJ/kg)/K]
AR	Residual Helmholtz energy	[J/mol]	[kJ/kg]
GR	Residual Gibbs energy	[J/mol]	[kJ/kg]
Ideal-gas contributions to the Helmholtz energy
PHIG00	Red. IG Helmholtz energy A0/RT	[-]	[-]
PHIG10	tau*[d(A0/RT)/d(tau)]	[-]	[-]
PHIG20	tau^2*[d^2(A0/RT)/d(tau)^2]	[-]	[-]
PHIG30	tau^3*[d^3(A0/RT)/d(tau)^3]	[-]	[-]
PHIG01	del*[d(A0/RT)/d(del)]	[-]	[-]
PHIG02	del^2*[d^2(A0/RT)/d(del)^2]	[-]	[-]
PHIG03	del^3*[d^3(A0/RT)/d(del)^3]	[-]	[-]
PHIG11	tau*del*[d^2(A0/RT)/d(tau)d(del)]	[-]	[-]
PHIG12	tau*del^2*[d^3(A0/RT)/d(tau)d(del)^2]	[-]	[-]
PHIG21	tau^2*del*[d^3(A0/RT)/d(tau)^2d(del)]	[-]	[-]
Residual contributions to the Helmholtz energy
PHIR00	Red. resid. Helmholtz energy Ar/RT	[-]	[-]
PHIR10	tau*[d(Ar/RT)/d(tau)]	[-]	[-]
PHIR20	tau^2*[d^2(Ar/RT)/d(tau)^2]	[-]	[-]
PHIR30	tau^3*[d^3(Ar/RT)/d(tau)^3]	[-]	[-]
PHIR01	del*[d(Ar/RT)/d(del)]	[-]	[-]
PHIR02	del^2*[d^2(Ar/RT)/d(del)^2]	[-]	[-]
PHIR03	del^3*[d^3(Ar/RT)/d(del)^3]	[-]	[-]
PHIR11	tau*del*[d^2(Ar/RT)/d(tau)d(del)]	[-]	[-]
PHIR12	tau*del^2*[d^3(Ar/RT)/d(tau)d(del)^2]	[-]	[-]
PHIR21	tau^2*del*[d^3(Ar/RT)/d(tau)^2d(del)]	[-]	[-]
Critical point and P,T maximums along isopleth (see above)
TC	Critical temperature of a pure fluid	[K]	[K]
PC	Critical pressure of a pure fluid	[kPa]	[kPa]
DC	Critical density of a pure fluid	[mol/dm^3]	[kg/m^3]
TCEST	Estimated critical temperature	[K]	[K]
PCEST	Estimated critical temperature	[kPa]	[kPa]
DCEST	Estimated critical density	[mol/dm^3]	[kg/m^3]
TMAXT	Temperature at cricondentherm	[K]	[K]
PMAXT	Pressure at cricondentherm	[kPa]	[kPa]
DMAXT	Density at cricondentherm	[mol/dm^3]	[kg/m^3]
TMAXP	Temperature at cricondenbar	[K]	[K]
PMAXP	Pressure at cricondenbar	[kPa]	[kPa]
DMAXP	Density at cricondenbar	[mol/dm^3]	[kg/m^3]
Reducing parameters
TRED	Reducing temperature	[K]	[K]
DRED	Reducing density	[mol/dm^3]	[kg/m^3]
TAU	Tc/T (or Tred/T)	[-]	[-]
DEL	D/Dc (or D/Dred)	[-]	[-]
Limits
TMIN	Minimum temperature of the EOS	[K]	[K]
TMAX	Maximum temperature of the EOS	[K]	[K]
DMAX	Maximum density of the EOS	[mol/dm^3]	[kg/m^3]
PMAX	Maximum pressure of the EOS	[kPa]	[kPa]
Transport, etc.
VIS	Viscosity	[uPa*s]	[uPa*s]
TCX	Thermal conductivity	[W/(m*K)]	[W/(m*K)]
PRANDTL	Prandlt number	[-]	[-]
TD	Thermal diffusivity	[cm^2/s]	[cm^2/s]
KV	Kinematic Viscosity	[cm^2/s]	[cm^2/s]
STN	Surface tension	[mN/m]	[mN/m]
DE	Dielectric constant	[-]	[-]
Heating values
SPHT	Specific heat input	[J/mol]	[kJ/kg]
HFRM	Heat of formation	[J/mol]	[kJ/kg]
HG	Gross (or superior) heating value	[J/mol]	[kJ/kg]
HN	Net (or inferior) heating value	[J/mol]	[kJ/kg]
HGLQ	Gross Heat. Val. (Liquid)	[J/mol]	[kJ/kg]
HNLQ	Net Heat. Val. (Liquid)	[J/mol]	[kJ/kg]
HGVOL	Gross HV (Ideal gas volume basis)	[MJ/m^3]	[MJ/m^3]
HNVOL	Net HV (Ideal gas volume basis)	[MJ/m^3]	[MJ/m^3]
HEATVAPZ	Heat of vaporization (for pure fluids)	[J/mol]	[kJ/kg]
HEATVAPZ_T	…at constant temperature (for mixtures)	[J/mol]	[kJ/kg]
HEATVAPZ_P	…at constant pressure (for mixtures)	[J/mol]	[kJ/kg]
HEATVALUE	Heating value (mass or molar basis)	[J/mol]	[kJ/kg]
Other properties
PINT	Internal pressure	[kPa]	[kPa]
PREP	Repulsive part of pressure	[kPa]	[kPa]
PATT	Attractive part of pressure	[kPa]	[kPa]
EXERGY	Flow Exergy	[J/mol]	[kJ/kg]
CEXERGY	Closed System Exergy	[J/mol]	[kJ/kg]
CSTAR	Critical flow factor	[-]	[-]
TMF	Throat mass flux	[kg/(m^2*s)]	[kg/(m^2*s)]
FPV	Supercompressibility	[-]	[-]
SUMFACT	Summation Factor	[-]	[-]
RDAIR	Relative Density in air (specific gravity)	[-]	[-]
RDH2O	Relative Density in water (specific gravity)	[-]	[-]
API	API Gravity	[-]	[-]
Fluid fixed points for mixtures
At the “true” critical point of the EOS dP/dD=0 and d^P/dD^2=0 at constant temperature
TCRIT	Critical temperature of component i	[K]	[K]
PCRIT	Critical pressure of component i	[kPa]	[kPa]
DCRIT	Critical density of component i	[mol/dm^3]	[kg/m^3]
TCTRUE	True EOS critical temp. of component i	[K]	[K]
DCTRUE	True EOS critical density of component i	[mol/dm^3]	[kg/m^3]
TTRP	Triple point temperature of component i	[K]	[K]
PTRP	Triple point pressure of component i	[kPa]	[kPa]
DTRP	Triple point density of component i	[mol/dm^3]	[kg/m^3]
TNBP	Normal boiling point temp. of comp. i	[K]	[K]
REOS	Gas constant of component i for EOS	[J/(mol*K)]	[(kJ/kg)/K]
MM	Molar mass of component i	[g/mol]	[g/mol]
ACF	Acentric factor of component i	[-]	[-]
DIPOLE	Dipole moment of component i	[debye]	[debye]
TREF	Ref. state temperature of component i	[K]	[K]
DREF	Ref. state pressure of component i	[kPa]	[kPa]
HREF	Ref. state enthalpy of comp. i at T0 and P0	[J/mol]	[kJ/kg]
SREF	Ref. state entropy of comp. i at T0 and P0	[J/(mol*K)]	[(kJ/kg)/K]
Transport properties as a function of component number
Viscosity=ETA0+ETAB2+ETAR+ETAC
Thermal conductivity=TCX0+TCXR+TCXC
ETA0	Dilute gas viscosity of component i	[uPa*s]	[uPa*s]
ETAB2	2nd virial viscosity of component i	[uPa*s]	[uPa*s]
ETAR	Residual viscosity of component i	[uPa*s]	[uPa*s]
ETAC	Viscosity critical enhance. of comp. i	[uPa*s]	[uPa*s]
TCX0	Dilute gas thermal cond. of comp. i	[W/(m*K)]	[W/(m*K)]
TCXR	Residual (background) cond. of comp. i	[W/(m*K)]	[W/(m*K)]
TCXC	Cond. crit. enhancement of comp. i	[W/(m*K)]	[W/(m*K)]
Mixture properties as a function of component number
K	K value (y/x) (not implemented, y unknown)	[-]	[-]
F	Fugacities	[kPa]	[kPa]
FC	Fugacity coefficients	[-]	[-]
CPOT	Chemical potentials	[J/mol]	[kJ/kg]
DADN	n*partial(alphar)/partial(ni)	[-]	[-]
DNADN	partial(n*alphar)/partial(ni)	[-]	[-]
XMOLE	Composition on a mole basis	[-]	[-]
XMASS	Composition on a mass basis	[-]	[-]
FIJMIX	Binary parameters (see REFPROP)

The dimension statements for these variables are (in Fortran):

parameter (ncmax=20)      ! Maximum number of components in the mixture
parameter (iPropMax=200)  ! Number of output properties available in ALLPROPS.
character*10000 hOut      ! hOut can actually be of any length.
character herr*255,hUnitsArray(iPropMax)*50
integer ierr,iUnits,iMass,iFlag,iUCodeArray(iPropMax) ! Note: as integer*4
double precision T,D,z(ncmax),Output(iPropMax)

Parameters:

• hOut [char ,in] :: Input string of properties to calculate. Inputs can be separated by spaces, commas, semicolons, or bars, but should not be mixed. For example, a proper string would be hOut=’T,P,D,H,E,S’, whereas an improperly defined string would be hOut=’T,P;D H|E,S’. Use of lower or upper case is not important. Some properties will return multiple values, for example, hOut=’F,Fc,XMOLE’ will return 12 properties for a four component system, these being F(1), F(2), F(3), F(4), Fc(1), Fc(2), etc. To retrieve the property of a single component, use, for example, hOut=’XMOLE(2),XMOLE(3)’.
• iUnits [int ,in] :: See subroutine REFPROP for a complete description of the iUnits input value. A negative value for iUnits indicates that the input temperature is given in K and density in mol/dm^3, (Refprop default units), otherwise T and D will be converted first to K and mol/dm^3. Do not use the negative value for the iUnits parameter everywhere, only in this one situation.
• iMass [int ,in] :: Specifies if the input composition is mole or mass based
• iFlag [int ,in] :: Turn on or off writing of labels and units to hUnitsArray (eventually may be multiple flags combined into one variable, similar to ABFLSH)
• T [double ,in] :: Temperature, with units based on the value of iUnits.
• D [double ,in] :: Density, with units based on the value of iUnits.
• z (20) [double ,in] :: Composition on a mole or mass basis (array of size ncmax=20)
• Output (200) [double ,out] :: Array of properties that were specified in the hOut string (array of size 200 dimensioned as double precision). The number -9999970 will be returned when errors occur or no input was requested.
• hUnits [char ,out] :: String with units. Will also contain error messages when necessary. The string will be empty if iFlag=0.
• iUCodeArray (200) [int ,out] :: Array (of size 200) with the values of iUCode(n) described in the REFPROP subroutine.
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• hOut_length [int ] :: length of variable hOut (default: 10000)
• hUnitsArray_length [int ] :: length of variable hUnitsArray (default: 10000)
• herr_length [int ] :: length of variable herr (default: 255)

Flags :

imass flags

0:Input compositions given in mole fractions 1:Input compositions given in mass fractions

iflag flags

0:Do not write anything to the hUnitsArray array, thus increasing the calculation speed. (String handling in Fortran is very computationally expensive.) 1:Write labels and units to the hUnitsArray array. 2:Return only the string number described under “iUCodeArray” below and the units. (No properties will be calculated.) -1:Write labels and units for only the first item.

subroutine ERRMSGdll(ierr, herr, herr_length)

Retrieve the last error message saved in calls to ERRNUM (but only if the ierr variable is not equal to zero). Write error messages to default output if iErrPrnt is active. The variable iErrPrnt in the common blocks must always be zero when compiling the DLL.

Outputs depend on variable iErrPrnt in the common blocks

• iErrPrnt= 0 - Error string not written (default)
• iErrPrnt=-1 - Error string written to screen
• iErrPrnt= 1 - Error string written to screen only if ierr is positive
• iErrPrnt=3,-3 - Same as 1 and -1, but program also pauses

Parameters:

• ierr [int ,in] :: Error number from the last call to ERRNUM
• herr [char ,out] :: Associated error string (character*255)
• herr_length [int ] :: length of variable herr (default: 255)

subroutine FLAGSdll(hFlag, jFlag, kFlag, ierr, herr, hFlag_length, herr_length)

Set flags for desired behavior from the program.

Table of flags in FLAGS function

hFlag	jFlag
Return errors	0 - Return only final messages (default). 1 - Return all intermediate messages. 2 - Do not return messages. This flag is not reset with a new call to SETUP.
Write errors	0 - Error strings not written to screen (default). -1 - Error string written to screen. 1 - Error string written to screen only if ierr is positive. 3,-3 - Same as 1 and -1, but program also pauses. This flag is not reset with a new call to SETUP.
Dir search	0 - Search for fluid files in alternate directories (as defined in OPENFL) (default). 1 - Do not search in directories other than the one set by the call to SETPATH, except for a ‘fluids’ subdirectory within the folder given in SETPATH. If the fluid files for the reference fluid(s) are not in the SETPATH directory, then transport properties may not be calculated. 2 - Make no additional checks if the fluid file is not found after the first attempt to open the file (for example, checking upper and lower case). This flag is never reset.
Cp0Ph0	1 - Change the ideal gas equation to Cp0. 2 - Change the ideal gas equation to PH0. The default is set by the value in the fluid file. Calling SETUP resets the equation to its default state as given in the fluid file.
PX0	0 - Use the fluid file as is for the ideal gas equation (default). 1 - Use the PX0 (or PH0 when no PX0 is available) for all calculations and turn off the call to SETREF. For mixtures, the reference state of “each pure component” will be used. This flag is never reset. When setting up the fluids through a call to the REFPROP subroutine, the SETREF flag described below will override this flag if turned on. Warning: Don’t use the Cp0Ph0 flag to attempt to switch back to Cp0 (h and s will be wrong)
Skip SETREF	0 - Call the SETREF routine to setup the reference state (default). 1 - Skip the call to SETREF. However, this means energy, enthalpy, and entropy will not be correct (but only by an offset to their usual values). This must be called before the call to SETUP, and is never reset.
Mixture reference or SETREF	0 - Do nothing (default). 2 - When calling subroutine REFPROP, call SETREF first with a value of 2 for the second entry. (See subroutine SETREF for details.) This must be called before the call to REFPROP (the subroutine in PROP_SUB.FOR), and is never reset.
Skip ECS	0 - Load the ECS fluids required for transport properties (for pure fluids in slots 21-40, and mixtures in slot 41). 1 - Don’t load the ECS fluids, only the requested fluids (this may deactivate pure fluid transport properties, and will deactivate all mixture transport calculations. This must be called before the call to SETUP, and is never reset.
Splines off	1 - Turn the splines off (assuming that they were turned on initially by a call to SATSPLN). Calling SETUP again will also turn off the splines.
Ignore bounds or Bounds	0 - Check all errors and respond accordingly (default). 1 - Ignore bounds for certain situations, such as calling SATT below the triple point or states above the melting line. This flag is never reset.
Cache	0 - Cache all calculated values (default). 1 - Cache only low level calculations, such as derivatives calculated in PHIFEQ. 2 - Cache only calculated properties in major subroutines such as SATT and SATP. 3 - No caching. This flag is not reset with a new call to SETUP.
Reset all	2 - Call RESETA to reset all cached values. This includes all flags set by calls to this routine, except for the use of a pure fluid in a mixture or reducing nc. Subroutine RESETA is always called by SETUP, but does not reset many of the flags set by calls to this routine.
Reset HMX or HMX	1 - Reset the caching flag so that the HMX.BNC file is read again on the next call to SETUP. This option is only useful during fitting mixture models or modifying the HMX.BNC file to add new interaction parameters, otherwise this flag will only slow down the program by forcing a reread of the mixture file. The output variable kFlag will be 0 or 1 to indicate whether or not the HMX.BNC will be read on the next call to SETUP.
Pure fluid	0 - Use full mixture equation of state loaded (default). <>0 - Use the pure fluid loaded in the slot specified by jFlag. This option is reset during the call to SETUP.
Component number or nc	nc - Reduce the number of fluids being used to nc. See SETNC routine for details. The output in kFlag will give the number of fluids in use, which can be useful even if this option has not been called to set nc. This option is reset during the call to SETUP.
Peng-Robinson or PR	0 - Turn off the Peng-Robinson equation of state (default). 2 - Use Peng-Robinson equation for all calculations. 3 - Use Peng-Robinson with translation term deactivated. This option is never reset.
kij Zero	0 - Use the fitted kij values found in the HMX.BNC file on the lines with PR1 (default). 1 - Set all kij values to those estimated in ESTPR (thus ignoring the ones on the PR1 lines in the HMX.BNC file). 2 - Set all kij values to zero. This option is never reset.
AGA8	0 - Turn off AGA8 and return to the fluids loaded from the call to SETUP (default) 1 - Turn on the use of the AGA8 DETAIL equation of state. If the AGA8 option is active, it overrides all other models. Unlike the GERG 2008 option, this model is active (or deactivated) immediately upon calling this routine. The AGA8 flag is never reset, thus recalling SETUP only changes the fluids, not the model.
GERG 2008 or GERG	0 - Set a flag to turn off GERG 2008 next time SETUP is called. 1 - Turn on the flag that will cause the GERG 2008 equation to be loaded next time SETUP is called This option MUST be called before SETUP. When turning off the GERG, call the SETUP routine again after calling this routine. Because the GERG model is not activated until SETUP is called, the value of kflag will be 1 until the next call to setup, at which time it will be set to 2 to indicate that it is fully active. When turning off the GERG model, the value of kflag will be -1 until the next call to setup, and then it will be reset to zero. The -1 indicates that it is still in use but waiting to be reset. This flag is never reset.
Gas constant or R	0 - Default is to use the most current gas constant for all fluids except nitrogen, argon, oxygen, ethylene, CO2, methane, and ethane. 1 - Use most current gas constant for all fluids (must be called after call to SETUP). 2 - Use gas constant from fluid files for each equation of state (must be called after call to SETUP). This option is reset during the call to SETUP.
Calorie	0 - Use a calorie to joule conversion value of 4.184 cal/J (default). 1 - Use the IT value of 4.1868 cal/J. This option is never reset.
Debug	0 - Turn off all debugging. 1 - In the REFPROP subroutine, write all input variables to a file called input.dat, and all output values to a file called output.dat 2 - In SETUP, write out the full path of the files that were either opened or tried to open. This option is never reset.

Parameters:

• hFlag [char ,in] :: Indicator for the option to set (letters in the string are case insensitive).
• jFlag [int ,in] :: Flag to choose what to do in each option. Send -999 to just obtain the current value of the flag.
• kFlag [int ,out] :: Current setting of the flag for the option identified by iFlag. (Returned regardless of the value of jFlag.)
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• hFlag_length [int ] :: length of variable hFlag (default: 255)
• herr_length [int ] :: length of variable herr (default: 255)

subroutine GETENUMdll(iFlag, hEnum, iEnum, ierr, herr, hEnum_length, herr_length)

Translate a string of letters into an integer value that can be used in calls to ALLPROPS0 to increase the speed of property calculations by eliminating string comparisons (which are time expensive in Fortran). This can be done once at the beginning of a program for all properties that will be used, and stored for later use as needed.

The input strings possible are described in subroutines ALLPROPS and GETUNIT.

Parameters:

• iFlag [int ,in] :: Flag to specify which type of enumerated value to return
• hEnum [char ,in] :: The string that will be used to return the enumerated value. Only uppercase letters are allowed to decrease the time required to process the values.
• iEnum [int ,out] :: The enumerated value that matches the string sent in hEnum.
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• hEnum_length [int ] :: length of variable hEnum (default: 255)
• herr_length [int ] :: length of variable herr (default: 255)

Flags :

iflag flags

0:Check all strings possible. 1:Check strings for property units only (e.g., SI, English, etc.). 2:Check property strings and those in #3 only. 3:Check property strings only that are not functions of T and D (for example, the critical point, acentric factor, limits of the EOS, etc.).

subroutine REFPROP1dll(hIn, hOut, iUnits, iMass, a, b, z, c, q, ierr, herr, hIn_length, hOut_length, herr_length)

Short version of subroutine REFPROP that eliminates the arrays and the need to send the fluid names each time.

The variable Output (which is an array) is not included here, rather the variable c returns the calculated value as a double precision variable, and thus only one value can be returned at a time. If the error number (ierr) is zero, the string contained in hUnits will be sent back in herr.

If q (quality) returns a value between zero and one (and thus the state is two-phase), the REFPROP routine will be needed to obtain the equilibrium compositions.

Parameters:

• hIn [char ,in] :: Input string of properties being sent to the routine.
• hOut [char ,in] :: Output string of properties to be calculated.
• iUnits [int ,in] :: The unit system to be used for the input and output properties (such as SI, English, etc.) See the details in the REFPROP subroutine for a complete description of the iUnits input value. NOTE: A mass based value for iUnits does not imply that the input and output compositions are on a mass basis, this is specified with the iMass variable.
• iMass [int ,in] :: Specifies if the input composition is mole or mass based
• a [double ,in] :: First input property as specified in the hIn variable.
• b [double ,in] :: Second input property as specified in the hIn variable.
• z (20) [double ,in] :: Composition on a mole or mass basis depending on the value sent in iMass (array of size ncmax=20).
• c [double ,out] :: Output value. The number -9999970 will be returned when errors occur, and the number -9999990 will be returned when nothing was calculated. Read the comments in the ALLPROPS routine for more information.
• q [double ,out] :: Vapor quality on a mole or mass basis depending on the value of iMass. (See subroutine ABFLSH for the definitions of values returned for this variable). To obtain the molar quality regardless of iMass, send “qmole” as an input in hIn, and vice-versa for “qmass”.
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• hIn_length [int ] :: length of variable hIn (default: 255)
• hOut_length [int ] :: length of variable hOut (default: 255)
• herr_length [int ] :: length of variable herr (default: 255)

Flags :

imass flags

0:Input compositions given in mole fractions, quality on a molar basis. 1:Input compositions given in mass fractions, quality on a mass basis. For two-phase states, the values in x and y will be returned on a mass basis if iMass=1. NOTE If the fluid string sent to this routine contains the word “mass” at the end (and thus contains the composition as well as the names of the fluids), this will have preference over the value of iMass when converting those compositions from a mass to a molar basis. However, compositions sent back will still be based on the value in iMass.

subroutine REFPROP2dll(hFld, hIn, hOut, iUnits, iFlag, a, b, z, Output, q, ierr, herr, hFld_length, hIn_length, hOut_length, herr_length)

Short version of subroutine REFPROP that eliminates the less used variables such as the x and y composition arrays. If the error number (ierr) is zero, the string contained in hUnits will be sent back in herr.

If q (quality) returns a value between zero and one (and thus the state is two-phase), the REFPROP routine will be needed to obtain the equilibrium compositions.

See subroutine REFPROP for further information on the input and output variables below.

Parameters:

• hFld [char ,in] :: Fluid string.
• hIn [char ,in] :: Input string of properties being sent to the routine.
• hOut [char ,in] :: Output string of properties to be calculated.
• iUnits [int ,in] :: The unit system to be used for the input and output properties (such as SI, English, etc.)
• iFlag [int ,in] :: Flag to specify if the routine SATSPLN should be called (where a value of 1 activates the call).
• a [double ,in] :: First input property as specified in the hIn variable.
• b [double ,in] :: Second input property as specified in the hIn variable.
• z (20) [double ,in] :: Molar composition (array of size ncmax=20).
• Output (200) [double ,out] :: Array of properties specified by the hOut string (array of size 200 dimensioned as double precision). The number -9999970 will be returned when errors occur, and the number -9999990 will be returned when nothing was calculated. Read the comments in the ALLPROPS routine to fully understand the contents of this array.
• q [double ,out] :: Vapor quality on a mole basis.
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• hFld_length [int ] :: length of variable hFld (default: 10000)
• hIn_length [int ] :: length of variable hIn (default: 255)
• hOut_length [int ] :: length of variable hOut (default: 255)
• herr_length [int ] :: length of variable herr (default: 255)

subroutine REFPROPdll(hFld, hIn, hOut, iUnits, iMass, iFlag, a, b, z, Output, hUnits, iUCode, x, y, x3, q, ierr, herr, hFld_length, hIn_length, hOut_length, hUnits_length, herr_length)

Calculate the properties identified in the hOut string for the inputs specified in the hIn string for the fluid or mixture given in the hFld string. The unit identifier for the properties should be passed in the iUnits variable (as described below). Compositions can be sent as mole fractions or mass fractions in the z array depending on the value of iMass.

Several items must be considered before using this routine. The most important is the speed of calculations. The original fortran code that called dedicated functions such as TPRHO, TPFLSH, PHFLSH, and so on (mostly given in FLSH_SUB.FOR) and the non-iterative functions such as THERM and TRNPRP requires very few (or no) string comparisons and are quite fast. Multiple string comparisons are made to determine the inputs and outputs the user has selected. Due to the limitation of Fortran in string parsing, this will cause a dramatic increase in the time required to make the calculations, such as two to three times as long as the dedicated functions. Thus the ease of use of this REFPROP subroutine versus the speed of calculation from the older routines must be considered before developing any application.

Information on hFld

For a pure fluid, hfld contains the name of the fluid file (with a path if needed).

For a mixture, it contains the names of the constituents in the mixture separated by semicolons or asterisks. Once the routine has been called with hFld set to the desired fluids, a space can be sent for all other calls that use the same fluid(s). For a predefined mixture, the extension “.mix” must be included. If the composition is included in the hFld variable, or if a predefined mixture is selected, the composition will be returned in the z array (on a molar or mass basis depending on iMass). That composition (or other compositions) must be sent in z in all subsequent calls to this routine. See subroutines SETFLUIDS and SETMIXTURE further below for additional information and examples.

Note: The speed of the program will be increased (sometimes substantially) if you call this routine only once with the name of the fluid and then never again unless your fluid or mixture changes. If your composition changes, send the new composition in the z array rather then sending a new string in the hfld variable.

Examples:

hFld='NITROGEN'
hFld='C:/Program Files (x86)/REFPROP/FLUIDS/R1234YF.FLD'
hFld='CARBON DIOXIDE'
hFld='METHANE;ETHANE;PROPANE;BUTANE;ISOBUTANE'
hFld='METHANE*ETHANE*PROPANE*BUTANE*ISOBUTANE'
hFld='R134a;0.3; R1234yf;0.3; R1234ze(Z);0.4'
hFld='CO2;0.2 * isobutane;0.3 * propadiene;0.5'
hFld='Nitrogen;Oxygen;Argon|0.4;0.3;0.3'
hFld='Nitrogen; Oxygen; Argon   ~   0.4; 0.3; 0.3'
hFld='R410A.MIX'

Information on hIn

Valid codes are T, P, D, E, H, S, and Q (temperature, pressure, density, energy, enthalpy, entropy, and quality). Two of these should be sent together to identify the contents of the a and b variables. For example, ‘TP’ would indicate inputs of temperature and pressure, and ‘TQ’ would indicate inputs of temperature and quality. A value of 0 for the quality will return a saturated liquid state, and a value of 1 will return a saturated vapor state. A value between 0 and 1 will return a two-phase state. Valid inputs are: TP, TD, TE, TH, TS, TQ, PD, PE, PH, PS, PQ, DE, DH, DS, DQ, ES, EQ, HS, HQ, SQ (or the inverse of any of these, e.g., QT) (hIn is not case sensitive, e.g., ‘TQ’ = ‘tq’). When q is >0 and <1, then the quality uses a molar basis when iMass=0, and a mass basis when iMass=1. The value of iUnits has no effect on the value of q (as either an input or output). The shortcuts Tsat and Psat can be used to specify a saturation state for the liquid for a pure fluid. To return, for example, the saturated vapor density, Dvap would be used as an output variable. The order of the properties being sent to the routine in the variables a and b has to be the same as the letters sent to hIn; for example, if hIn is ‘QT’, then a=q and b=T.

The ABFLSH routine is called to determine the phase of the inputs (liquid, vapor, or 2-phase), and then the appropriate iterative routine will be called to obtain the independent properties of the equations of state: temperature and density. For subsequent calculations for properties that are in the single phase, use the code TD&, where the symbol & indicates the single phase state. The time required with the use of TD& is negligible compared to that required for the iterative solution called by ABFLSH. However, the properties sent to this routine and the calculated outputs are cached to avoid additional iterative calls when the solution has already been determined. Be sure to read the warnings at the top of the ALLPROPS routine for additional information.

Flags to specify certain phases are listed below, for example, ‘TD>’ would specify an input state in the liquid phase but which would normally be two-phase. Those available are:

• **> or **L: When the letter ‘L’ is attached after the two letters that specify the input properties (such as ‘TP’), the routine will assume that the input properties are in the single phase liquid region, or are within the two-phase area as a metastable state. For example: TP>, PH>, HSL.
• **< or **V: The letter ‘V’ (or the sign ‘<’) specifies that the input state for the properties listed in the first two letters is in the single phase vapor (including metastable states). For example: TP<, PH<, HSV.
• TH< or TH>: Inputs of temperature and enthalpy (or occasionally temperature and internal energy) generally have two valid states. To obtain the root with the higher pressure, use TH> or TE>, and for the lower pressure use TH< or TE<.
• *MELT: Return properties at the melting point where the input property is specified by the *, for example TMELT requires the temperature for the input variable a, PMELT requires the pressure for input variable a, and so on.
• *SUBL: Return properties at the sublimation point, as described above for the melting point.
• CRIT: Return properties at the critical point (for example, hIn=’CRIT’ and hOut=’S’ would return the entropy at Tc and Dc). For a mixture, the critical point defined by the equation of state is only available if the SATSPLN routine has been called, otherwise an estimated value is returned.
• TRIP: Return liquid phase properties at the triple point.
• NBP: Return properties at the normal boiling point.
• DSAT: Return the saturation properties for the input density.
• HSAT, HSAT2: Enthalpy can be doubled valued in the vapor phase for some fluids. In such a situation, HSAT2 will return the root with the lower temperature.
• SSAT, SSAT2, SSAT3: Entropy can be doubled or triple valued in the vapor phase for some fluids (see butane for example). In such a situation, SSAT will return the root at the highest temperature, SSAT2 will return the middle root, and SSAT3 will return the root with the lowest temperature.

Various flags are available that can be sent to this routine in the variable hIn to gain access to all other features of the Refprop program. These cannot be combined as multiple inputs in hIn:

• FLAGS: Call the FLAGS routine at the bottom of this file to initialize the options available for controlling certain aspects of the Refprop program. Some of these include caching properties, turning on/off different types of equations of state (Peng-Robinson, GERG-2008, and AGA-8), the calorie to Joule definition, and so on. The flag string (the first input to the FLAGS routine) should be sent in hOut and the flag option should be sent in iFlag. The output (3rd variable in the routine) is returned in iUCode. See the FLAGS routine for further information. The variable hFld for the REFPROP routine should be left blank when using this option.

• EOSMIN: Return the property specified in hOut at the minimum temperature allowed in the equation of state. This is generally at the triple point in the liquid phase. Note that an input of P or D will not return the obvious minimum (zero), but the pressure and density at the liquid phase triple point (or lower temperature limit for a mixture). For water, the triple point T is still returned, even though lower temperatures are possible.

• EOSMAX: Return the maximum temperature, pressure, or density (as specified in hOut) for the equation of state. The maximum density of the equation of state does not occur at the maximum pressure and temperature. Only T, P, or D can be returned one at a time to emphasize that properties at Tmax and Pmax are not the same as at Tmax and Dmax.

• SETREF: Call the SETREF routine. The reference state (DEF, NBP, IIR, ASH, OTH, OT0, or NA) should be sent in hOut. For the OTH and OT0 options, the values of h0, s0, T0, and P0 should be included in the hOut variable, separated by semicolons. For example:

  hOut='OTH;10.;1.;323.15;101.325'
  

  This would set the enthalpy to 10 J/mol and the entropy to 1 J/mol-K at 323.15 K and 101.325 kPa. In the GUI is an option for mixtures to set the reference state to either the composition in use or to each pure fluid. To set this option through the DLL, a value of either 1 or 2 should be sent to this routine in the variable a. This will set the variable labeled ixflag in subroutione SETREF in the SETUP.FOR file. All other options for this command are also explained in the SETUP.FOR file.

• SETREFOFF: Turn off the inputs that were sent in the option above.

• PATH: Call the SETPATH routine with the path given in hFld.

• SATSPLN: Call the SATSPLN routine for the input composition (as described in the SAT_SUB.FOR file). The fluid name or mixture names and the composition must be sent with this command or have already been setup before this is called. This command is identical to calling this routine with iFlag=1, except that it can be issued at any time.

Information on hOut

String output is returned in hUnits. Numerical output is returned in Output(1). For flags used to obtain a value of a particular fluid in a mixture, the component number should be added after the command, such as NAME(3) or FDIR(1). Only one string output can be requested at a time for the following flags, down to the line that says DLL#. Use the ALLPROPS routine to return multiple strings for all the components in the mixture. This is done without using the component number, e.g., sending “NAME” to that routine. For numerical values, multiple inputs can be requested here, and must be separated by spaces, commas, semicolons, or bars, but these separators should not be mixed. See subroutine ALLPROPS (which follows this routine) for further information.

• ALTID: Return the alternative fluid whose mixing rules are used when others are not available.
• CAS#: Return the CAS number.
• CHEMFORM: Return the short chemical formula.
• SYNONYM: Return the synonym found on the fifth line in the fluid files.
• FAMILY: Return the family class used for several predictive schemes.
• FLDNAME: Return the fluid file name sent to the SETUP routine.
• HASH: Return the hash number.
• INCHI: Return the INCHI string.
• INCHIKEY: Return the INCHI key.
• LONGNAME: Return the long fluid name given in the 3rd line of the fluid files.
• SAFETY: Return the ASHRAE 34 classification.
• NAME: Return the fluid short name.
• NCOMP: Return the number of components.
• UNNUMBER: Return the UN number.
• DOI_###(#): Return the DOI of the equation given by the three letters following the underscore, where the valid letters are EOS for equation of state, VIS for viscosity, TCX for thermal conductivity, STN for surface tension, DIE for dielectic constant, MLT for melting line, and SBL for sublimation line. For example, DOI_EOS would return the DOI for the equation of state. For mixtures, the component must be specified at the end in the parenthesis, for example, DOI_VIS(3).
• WEB_###(#): Return the web address for the equation given by the three letters following the underscore, as explained in the DOI section.
• REFSTATE: Return the reference state in use (NBP, IIR, ASH, OTH, etc.).
• GWP: Return the global warming potential (found in the fluid file header).
• ODP: Return the ozone depletion potential (found in the fluid file header).
• FDIR: Return the location (directory) of the fluid file. The directory is returned in both the hUnits string and in herr if no other error occurred (paths that are more than 50 characters long are truncated in hUnits). For mixtures, send FDIR(2), etc., to get the path of the second fluid and so on.
• UNITSTRING: Return the units of the property (e.g., K, psia, kg/m^3, J/mol, etc.) identified in hIn for the unit system defined in hFld (e.g., SI, E, etc.). The input values for hIn are the labels described in the ALLPROPS routine. For example, ‘D2DDP2’ would return ‘(kg/m^3)/MPa^2’ for ‘SI’ inputs.
• UNITNUMB: Return in iUCode the integer value associated with a particular set of units defined in hFld (SI, E, etc.). This integer value can then be used in subsequent calls for the iUnits variable.
• UNITS: Perform both operations in UNITSTRING and UNITNUMB.
• UNITCONV: Convert the property contained in the variable a from units given in hFLD to units given in hIn. The unit strings are given much further below. When converting from mole to mass units (or vice versa), the molar mass must be sent in the variable b. The type of property (as specified in the CONVUNITS subroutine) must be appended to the string in hOut, for example, hOut=’UNITCONV_T’ or hOut=’UNITCONV_D’.
• UNITUSER, UNITUSER2: Set a predefined set of units based on the user’s need. Two different sets can be assigned depending on the input sent to the routine. The variable hIn contains the numbers that are specified by the enumerations in the CONSTS.INC file, separated by semicolons. For example, hIn=’0;157;0;0;0;403;0;0;0;0’ would set the pressure to use units of atm and the speed of sound to use units of km/h. The numbers are listed in the order of T, P, D, H, S, W, I, E, K, and N (temperature, pressure, density, enthalpy, entropy, speed of sound, kinematic viscosity, viscosity, thermal conductivity, and surface tension). Because the enumerations might change, it is best to build this string with the enumerations listed in the CONSTS.INC file rather than hard coding the numbers as shown above.
• DLL#: Return the version number of the DLL in iUCode and the string value in hUnits.
• PHASE: Return the phase of the state for the input fluids and properties. See subroutine PHASE for a listing of all possibilities. The output is sent back in the hUnits variable. No other command can be sent with this one since hUnits is not an array.
• FULLCHEMFORM: Return the long chemical formula.
• HEATINGVALUE: Return the upper heating value.
• LIQUIDFLUIDSTRING: Return a string that contains the fluid names and compositions for the liquid phase of a two-phase state.
• VAPORFLUIDSTRING: Return a string that contains the fluid names and compositions for the vapor phase of a two-phase state. For example, “R32;R125|0.25;0.75”. The string is passed back in hUnits.
• QMOLE: Return the molar quality for 2-phase states.
• QMASS: Return the mass quality for 2-phase states.
• XMASS: Return the mass compositions in the Output array as with the X command. See comment about Qmass.
• XLIQ: Return the mass or molar liquid compositions (depending on the value of iMass) for 2-phase states.
• XVAP: Return the mass or molar vapor compositions (depending on the value of iMass) for 2-phase states.
• XMOLELIQ: Return the liquid compositions for 2-phase states on a mole basis regardless of the iMass variable.
• XMOLEVAP: Return the vapor compositions for 2-phase states on a mole basis regardless of the iMass variable.
• XMASSLIQ: Return the liquid compositions for 2-phase states on a mass basis regardless of the iMass variable.
• XMASSVAP: Return the vapor compositions for 2-phase states on a mass basis regardless of the iMass variable.
• *LIQ: (where * is T, P, D, etc.) Return the liquid saturation properties for the property listed as the first letter. This is only valid for saturation states or 2-phase states.
• *VAP: (where * is T, P, D, etc.) Return the vapor saturation properties for the property listed as the first letter. This is only valid for saturation states or 2-phase states.
• FIJMIX: Return the mixing parameters in the first six slots of the variable Output for the binary mixture identified by the values in the a and b variables (i.e., integer values are sent in double precision variables). The mixing rule is returned in the hUnits string.

Information on iUnits

Multiple unit systems are available for use in property values, such as the SI system, English system, mixed sets, and so forth. Each set is identified with an enumerated value, which is sent as an input code in iUnits.

<FORTRAN ONLY> The enumerated value for the different unit systems are listed below and in the CONSTS.INC file, which can be included in your FORTRAN program, as such:

include 'CONSTS.INC'

Warning

Do NOT include any other INC file in your programs

The enumerated values for the unit systems are given by the parameters

• iUnitsMolSI
• iUnitsSI
• …

</FORTRAN ONLY>

In all environments other than FORTRAN, the iUnits variable should be retrieved from the GETENUM function with a call like:

GETENUMdll(0,'MOLAR BASE SI',iEnum,ierr,herr)

Warning

The integer values for iUnits given below should NEVER be used directly, you should always retrieve the enumerated value from GETENUM. This is to allow the developers of Refprop flexibility in the future.

The unit systems used in Refprop are as follows:

                 DEFAULT     MOLAR SI    MASS SI       SI WITH C
iUnits --->      0           1           2             3
Temperature      K           K           K             C
Pressure         kPa         MPa         MPa           MPa
Density          mol/dm^3    mol/dm^3    kg/m^3        kg/m^3
Enthalpy         J/mol       J/mol       J/g           J/g
Entropy          (J/mol)/K   (J/mol)/K   (J/g)/K       (J/g)/K
Speed            m/s         m/s         m/s           m/s
Kinematic vis.   cm^2/s      cm^2/s      cm^2/s        cm^2/s
Viscosity        uPa-s       uPa-s       uPa-s         uPa-s
Thermal cond.    W/(m-K)     mW/(m-K)    mW/(m-K)      mW/(m-K)
Surface tension  N/m         mN/m        mN/m          mN/m
Molar Mass       g/mol       g/mol       g/mol         g/mol

                 MOLAR       MASS
                 BASE SI     BASE SI     ENGLISH       MOLAR ENGLISH
iUnits --->      20          21          5             6
Temperature      K           K           F             F
Pressure         Pa          Pa          psia          psia
Density          mol/m^3     kg/m^3      lbm/ft^3      lbmol/ft^3
Enthalpy         J/mol       J/kg        Btu/lbm       Btu/lbmol
Entropy          (J/mol)/K   (J/kg)/K    (Btu/lbm)/R   (Btu/lbmol)/R
Speed            m/s         m/s         ft/s          ft/s
Kinematic vis.   m^2/s       m^2/s       ft^2/s        ft^2/s
Viscosity        Pa-s        Pa-s        lbm/(ft-s)    lbm/(ft-s)
Thermal cond.    W/(m-K)     W/(m-K)     Btu/(h-ft-R)  Btu/(h-ft-R)
Surface tension  N/m         N/m         lbf/ft        lbf/ft
Molar Mass       kg/mol      kg/mol      lbm/lbmol     lbm/lbmol

                 MKS         CGS         MIXED         MEUNITS
iUnits --->      7           8           9             10
Temperature      K           K           K             C
Pressure         kPa         MPa         psia          bar
Density          kg/m^3      g/cm^3      g/cm^3        g/cm^3
Enthalpy         J/g         J/g         J/g           J/g
Entropy          (J/g)/K     (J/g)/K     (J/g)/K       (J/g)/K
Speed            m/s         cm/s        m/s           cm/s
Kinematic vis.   cm^2/s      cm^2/s      cm^2/s        cm^2/s
Viscosity        uPa-s       uPa-s       uPa-s         cpoise
Thermal cond.    W/(m-K)     mW/(m-K)    mW/(m-K)      mW/(m-K)
Surface tension  mN/m        dyne/cm     mN/m          mN/m
Molar Mass       g/mol       g/mol       g/mol         g/mol

                 USER (can be changed by calling the REFPROP subroutine)
iUnits --->      11
Temperature      C
Pressure         psig
Density          kg/m^3
Enthalpy         J/g
Entropy          (J/g)/K
Speed            m/s
Kinematic vis.   cm^2/s
Viscosity        mPa-s
Thermal cond.    W/(m-K)
Surface tension  N/m
Molar Mass       g/mol

Information on iUCode output

The iUCode variable uses a four digit code that specifies the units of the property:

• Left digit : Energy unit in J/mol or kJ/kg
• Left middle digit : Density unit in mol/dm^3 or kg/m^3
• Right middle digit : Pressure unit in kPa
• Right digit : Temperature unit in K

Each digit indicates the power of the unit, for example, a value of 2 for the temperature digit corresponding to K^2. Values from 6 to 9 specify a negative power digit, for example, a value of 8 would be 1/kPa^2.

The following values give other examples:

1000    J/mol
0100    mol/dm^3
0010    kPa
0001    K
0000    -  (a value of zero assumes a dimensionless unit)
9000    1/(J/mol)
0910    kPa/(mol/dm^3)
0190    (mol/dm^3)/kPa
8765    K^5/[(J/mol)^2*(mol/dm^3)^3*kPa^4]
2082    (J/mol)^2*K^2/kPa^2
0830    kPa^3/(mol/dm^3)^2
9281    (mol/dm^3)^2*K/[(J/mol)*kPa^2]
8139    (mol/dm^3)*kPa^3/[(J/mol)^2*K]
2288    (J/mol)^2*(mol/dm^3)^2/[kPa^2*K^2]
1764    (J/mol)*K^4/[(mol/dm^3)^3*kPa^4]
4857    (J/mol)^4*kPa^5/[(mol/dm^3)^2*K^3]
2730    (J/mol)^2*kPa^3/(mol/dm^3)^3
6666    1/[(J/mol)^4*(mol/dm^3)^4*kPa^4*K^4]

Negative values represent special units not built on these four property types:

Property	Parameter	Current Value (but subject to change)
Speed of sound	iUTypeW	-9
Viscosity	iUTypeU	-10
Thermal conductivity	iUTypeK	-11
Surface tension	iUTypeN	-12
Quality	iUType0	-13
Molar mass	iUTypeM	-14
Kinematic viscosity	iUTypeI	-17
Mass flux	iUTypeF	-27
Heating value (volume)	iUTypeG	-37
Dipole moment	iUTypeB	-38

The dimension statements for these variables are (in Fortran):

parameter (ncmax=20)                       !Maximum number of components in the mixture
parameter (iPropMax=200)                   !Number of output properties available in ALLPROPS.
character*255 hFld,hIn,hOut,hUnits,herr              !hFld, hIn, and hOut can actually be of any length.
integer iUnits,iMass,iFlag,ierr,iUCode               !Note: as integer*4
double precision a,b,q,Output(iPropMax),z(ncmax),x(ncmax),y(ncmax),x3(ncmax)

Parameters:

• hFld [char ,in] :: Fluid string. See above
• hIn [char ,in] :: Input string of properties being sent to the routine.
• hOut [char ,in] :: Various flags are available to gain access to all other features of the Refprop program.
• iUnits [int ,in] :: The unit system to be used for the input and output properties (such as SI, English, etc.) See the details much further below for a complete description of the iUnits input value. NOTE A mass based value for iUnits does not imply that the input and output compositions are on a mass basis, this is specified with the iMass variable.
• iMass [int ,in] :: Specifies if the input composition is mole or mass based
• iFlag [int ,in] :: Flag to specify if the routine SATSPLN should be called (where a value of 1 activates the call). (Eventually this variable may be used to send multiple flags combined in this flag.)
• a [double ,in] :: First input property as specified in the hIn variable
• b [double ,in] :: Second input property as specified in the hIn variable
• z (20) [double ,in] :: Composition on a mole or mass basis depending on the value sent in iMass (array of size ncmax=20).
• Output (200) [double ,out] :: Array of properties specified by the hOut string (array of size 200 dimensioned as double precision). The number -9999970 will be returned when errors occur, and the number -9999990 will be returned when nothing was calculated. Read the comments in the ALLPROPS routine to fully understand the contents of this array.
• hUnits [char ,out] :: The units for the first property in the Output array. Strings such as a fluid name may also be passed back in this position. To obtain the units for all of the properties sent to the string, call the ALLPROPS routine instead.
• iUCode [int ,out] :: Unit code that represents the units of the first property in the Output array. See below for further details.
• x (20) [double ,out] :: Composition of the liquid phase (array of mole fractions of size 20) for two-phase states on a mole or mass basis depending on the value of iMass.
• y (20) [double ,out] :: Composition of the vapor phase (array of mole fractions of size 20) for two-phase states on a mole or mass basis depending on the value of iMass.
• x3 (20) [double ,out] :: Reserved for returning the composition of a second liquid phase for LLE or VLLE.
• q [double ,out] :: Vapor quality on a mole or mass basis depending on the value of iMass. (See subroutine ABFLSH for the definitions of values returned for this variable). To obtain the molar quality regardless of iMass, send “qmole” as an input in hIn, and vice-versa for “qmass”.
• ierr [int ,out] :: Error flag
• herr [char ,out] :: Error string (character*255)
• hFld_length [int ] :: length of variable hFld (default: 10000)
• hIn_length [int ] :: length of variable hIn (default: 255)
• hOut_length [int ] :: length of variable hOut (default: 255)
• hUnits_length [int ] :: length of variable hUnits (default: 255)
• herr_length [int ] :: length of variable herr (default: 255)

Flags :

imass flags

0:Input compositions given in mole fractions, quality on a molar basis. 1:Input compositions given in mass fractions, quality on a mass basis. For two-phase states, the values in x and y will be returned on a mass basis if iMass=1. NOTE If the fluid string sent to this routine contains the word “mass” at the end (and thus contains the composition as well as the names of the fluids), this will have preference over the value of iMass when converting those compositions from a mass to a molar basis. However, compositions sent back will still be based on the value in iMass.

subroutine SETFLUIDSdll(hFld, ierr, hFld_length)

Call the SETUP routine without the need to pass ncomp, hrf, hFmix, or herr, or to declare the length of hfld as 255 or 10000 bytes long. For a pure fluid, hfld simply contains the name of the fluid file (with a path if needed). For a mixture, it contains the names of the constituents in the mixture separated by a |, a semicolon, or an asterisk. To load a predefined mixture, call the SETMIXTURE subroutine (which must return the composition array and thus cannot be included here). If it is necessary to set the reference state, call SETUP instead. If ierr comes back non-zero, call the ERRMSG routine to obtain it.

Examples:

call SETFLUIDS ('ARGON',ierr)    (load argon as a pure fluid)
call SETFLUIDS ('FLUIDS/NITROGEN.FLD|FLUIDS/ARGON.FLD|FLUIDS/OXYGEN.FLD|',ierr)  (for the air mixture, but giving a path as well)
call SETFLUIDS ('AIR.PPF',ierr)  (load the air mixture, but read from the pseudo-pure file; properties will be slightly different from the *.mix file since they are different models)
call SETFLUIDS ('methane * ethane * propane * butane',ierr)

Parameters:

• hFld [char ,in] :: String of any character length containing the fluid file names
• ierr [int ,out] :: Error flag
• hFld_length [int ] :: length of variable hFld (default: 10000)

Flags :

ierr flags

0:Successful (Values are identical to SETUP; a 109 is returned if the number of fluids in hfld is less than icomp.)

subroutine SETMIXTUREdll(hMixNme, z, ierr, hMixNme_length)

Call the SETMIX routine for a predefined mixture without the need to pass hFmix, hrf, ncc, hf, or herr. It is not necessary to declare the length of hMixNme as 255 bytes long. A path can be included if needed. The extension “.mix” is not required. If it is necessary to set the reference state, call subroutine FLAGS first. The composition of the mixture will be returned in the z array. If ierr comes back non-zero, call the ERRMSG routine to obtain it.

Examples:

call SETMIXTURE ('AIR.MIX',z,ierr) ! load the air mixture from the AIR.MIX file
call SETMIXTURE ('C:/REFPROP/MIXTURES/AIR.MIX',z,ierr)    read the AIR.MIX file from the C:/REFPROP/MIXTURES directory
call SETMIXTURE ('R410A.MIX',z,ierr) ! load the R410A mixture, the composition will be returned on a mole percent basis in the z array.
call SETMIXTURE ('R410A',z,ierr)  ! works the same as above for predefined refrigerant mixtures that start with R4 or R5.

Parameters:

• hMixNme [char ,in] :: String of any character length containing the mixture file name
• z (20) [double ,out] :: Composition array (mole fractions)
• ierr [int ,out] :: Error flag
• hMixNme_length [int ] :: length of variable hMixNme (default: 10000)

Flags :

ierr flags

0:Successful (Values are identical to SETMIX)

subroutine SETPATHdll(hpth, hpth_length)

Set the path where the fluid files are located.

Parameters:

• hpth [char ,in] :: Location of the fluid files (character*255) The path does not need to contain the ending “/” and it can point directly to the location where the DLL is stored if a fluids subdirectory (with the corresponding fluid files) is located there, for example, hpth=’C:/Program Files (x86)/REFPROP’
• hpth_length [int ] :: length of variable hpth (default: 255)