Answers to Frequently Asked Questions
The following information gives answers to some of the most frequently asked questions concerning the REFPROP program (www.nist.gov/srd/nist23.cfm). To download any of the files listed below, right-click on the file and select Save Target As... and then add the file to your Refprop or other appropriate directory. Sections with new information added during the last several months are identified with a «. For questions not answered here, please see the user's guide at www.nist.gov/srd/upload/REFPROP9.pdf
«Please note:
There have been a number of users who have had problems with the Excel
link to Refprop. In some of these cases
and in other situations we have found that the refprop.dll file had also been
installed in either the c:\windows directory or the c:\windows\system32
directory. If you experience problems,
please do a full hard drive search for refprop.dll and delete all occurrences
except the one in your c:\program files\refprop directory.
«There are a few changes in
version 9.0 that may confuse you when you first run the program. The number of fluids will appear to be much
shorter. Look under Substance/Specify
Fluid Set and you will see the ability to select a set of fluids rather than
list all of them. In the
Options/Properties menu, the composition box is now missing from the
Thermodynamic tab; you will find it in the Mixtures tab along with other
properties that are generally displayed only for mixtures. When copying data from a table, the headers
are no longer copied with the data. If
you like that feature, select it in Options/Preferences, then save the
defaults.prf file under Options/Save Current Options. The "Refprop with Instructions and
Help.xls" file has been joined with the Refprop.xls file and is no longer
distributed. Concerning the Fortran
files and the calling routines to the DLL, all of the inputs/outputs to the routines
are the same as those to 8.0 so your own code will not have to be updated. Just replace your old DLL with that from 9.0
and you will be set to go (of course you will also need the new FLD files and
the HMX.BNC file).
1. Reference States (enthalpy and entropy differences)
2. REFPROP is a Program, not a Database Containing Measurements
3. Referencing the REFPROP Program in Publications
5.
GERG-2008 Equation of State for Natural Gas Mixtures
6.
Changing Fluids and Calling SETUP Multiple
Times
Questions about Installing the Program
8.
Help File
Fluids
10.
Humid Air
11. Solids
12. Transport
Properties for Nitrogen, Oxygen, Argon, and Air
13. Transport Properties for
Pseudo-pure Fluids, Adding Pure Fluids to a Mixture Setup
Two-Phase States
14. Defining Two-Phase States for Pure Fluids
15. Multiple
and Metastable States
16. FLSH
Routines and Metastable States
Error Messages
17.
Convergence Failures and Forcing Phase
Calculations
18. Mixture Error
Messages
Linking with other Applications
19.
Required Fluids for Distribution
20. Mixture Files
21. C Applications
22. .NET Applications«
27. MatLab
Applications«
28.
Excel Applications«
Reference
States. For differences
in enthalpy and entropy between the Refprop graphical interface and the Refprop
Excel sample spreadsheet, or for differences in enthalpy and entropy between
Refprop and tables of properties given in handbooks:
The absolute values of enthalpy, entropy, and energy at a single state point
are meaningless. It is only the difference between two different state
points that matter. Thus, the value for a single state point can be set
to any arbitrary value. Many handbooks set the arbitrary state point so
that the values of these properties are positive for most liquid or gas
states. The user can change the values of the arbitrary state points by
going to the Options/Reference State menu.
For mixtures, there are additional options that can be set to affect the manner
in which these properties are calculated. The preset values sent out with
Refprop 7.0 are different between the graphical interface and the Excel file.
In the Options/Reference State menu, there are two choices at the bottom
of the menu on the far right. By changing this option, the two programs
will then return the same values. This option can be permanently saved in
the graphical interface by selecting Options/Save Options, and the
saving the options under the file name defaults.prf. To change the
default in the Excel file, press Alt-F11 to bring up the VB code. If the
code does not appear, make sure the project explorer is visible (View/Project
Explorer), and then click on modules and then on module1. Search for
the call to SETREF, and change the second input from 2& to 1&.
More information on this can be found in your Refprop\Fortran directory in the
file SETUP.FOR under the SETREF subroutine.
To permanently change the default setting for a pure fluid, edit the fluid file
and look at the 14th line of the file, which will appear similar to
this:
IIR
!default reference state
Remove this line and add two lines in its place, similar to the following:
OTH
!default reference state
300.0 1.0 10000.0
100.0 !tref, Pref, Href, Sref
These lines will set the enthalpy to 10000 J/mol and the entropy to 100 J/mol-K
at 300 K and 1 kPa. These values can be changed to any other desired
values.
REFPROP is a Program, not a Database Containing Measurements. The REFPROP "database" is actually a program and does not contain any experimental information, aside from the critical and triple points of the pure fluids. The program uses equations for the thermodynamic and transport properties to calculate the state points of the fluid or mixture. These equations are the most accurate equations available world wide. A link to one of these equations for R-125 is given below. Their high accuracy is obtained through many coefficients in the equations, and thus the calculation speed will be slower than other equations such as the Peng-Robinson cubic equations. The equations are generally valid over the entire vapor and liquid regions of the fluid, including supercritical states; the upper temperature limit is usually near the point of decomposition of the fluid, and the upper pressure (or density) limit is defined by the melting line of the substance.
Referencing
the REFPROP Program in Publications.
The following reference can
be used to cite the REFPROP program in publications:
Lemmon, E.W., Huber, M.L., McLinden,
M.O. NIST Standard Reference Database 23: Reference Fluid
Thermodynamic and Transport Properties-REFPROP, Version 9.0, National Institute
of Standards and Technology, Standard Reference Data Program, Gaithersburg,
2010.
Additionally, users should cite the reference for either the equation of state
or the transport equations used in their work, for example, if you used
calculations for CO2, you will find the reference for the equation
of state under the Options/Fluid Information option in Refprop and you should
cite the reference given under that option, like this:
Span, R. and Wagner, W., J. Phys. Chem. Ref. Data, 25(6):1509-1596, 1996.
Updates
to Version 9.0. Version 9.0 is now the current release and
there are no updates to this version.
Several problems in version 9 have been found since its release, if any
of these affect you please contact Eric Lemmon.
1. The calculation of d2p/dT2
at constant density is incorrect.
2. The reference state for R1234yf and
ze should be changed from NBP to IIR.
Updated files are given further below.
3. Calculation of isobars for pure
fluids at pressures less than the triple point pressure may incorrectly return
properties in the liquid phase rather than the vapor phase.
4. The manual REFPROP9.PDF and the
UserInformation sheet in Refprop.xls incorrectly listed isobutene instead of
isobutane for R430A. (However, the
graphical interface and mixture file are correct.)
5. Transport properties for the
siloxanes have been added and the fluid files can be obtained by contacting
Eric Lemmon.
GERG-2008
Equation of State for Natural Gas Mixtures. The
current equation of state for calculating the properties of natural gas
mixtures is the GERG-2008 equation (GERG is the European Gas Research
Group). This equation is based on an
excess Helmholtz energy approach using pure fluid equations of state (either
those specified by GERG, or the current standards that have slightly higher
accuracies) and a mixture model that specifies the excess contribution. The 2008 version is an extension of the 2004
version, containing the additional fluids nonane, decane, and hydrogen sulfide
in addition to methane, nitrogen, carbon dioxide, ethane, propane, n-butane,
isobutane, n-pentane, isopentane, n-hexane, n-heptane, n-octane, hydrogen,
oxygen, carbon monoxide, water, helium, and argon. The 2008 edition also replaced the pure fluid
equations of state for isopentane and carbon monoxide with published
versions. These two models are fully
described in the following publications:
Kunz, O. and Wagner, W., The GERG-2008 Wide-Range Equation of State for Natural
Gases and Other Mixtures: An Expansion
of GERG-2004, to be submitted to J. Chem. Eng. Data, 2012.
Kunz, O., Klimeck, R., Wagner, W., and Jaescke, M., The GERG-2004 Wide-Range
Equation of State for Natural Gases and Other Mixtures: GERG Technical
Monograph 15 and Fortschr.-Ber. VDI, Reihe 6, Nr. 557, VDI Verlag, Düsseldorf,
2007.
In the Refprop 9.0 program, the natural gas equation of state has been expanded
to include ethylene, propylene, methanol, ethanol, toluene, benzene, cyclohexane,
sulfur dioxide, ammonia, dodecane, acetone, and butylene. When selecting the option to use the full
GERG-2008 equation of state (either through the GUI or by calling the
“GERG2004” subroutine), the use of these additional fluids is still allowed. This is not the same as when the AGA-8
equation of state is selected, in which case only the original 21 fluids (same
as those in the GERG-2008 model) are allowed.
Changing Fluids
and Calling SETUP Multiple Times. Calling SETUP (or SETUPdll) many many times can
result in a memory loss error and in a substantial increase of computation
speed. In many situations, it is better
to load all of the fluids at the start of the program, calling SETUP only once. You can then switch between fluids through
the use of calls to SETNC and PUREFLD.
The example below shows how this can be done for a mixture combined with
several pure fluids. If two different
mixtures are required, load all fluids and set the composition to 0 for those
fluids not involved in a particular application. This could easily be done by using two
different arrays for the composition.
EX-MULTI.FOR
Installation Problems. In some applications where calculations fail
after installing version 9.0, the old DLL from version 7.0 or 8.0 may be hiding
in your Windows\System32 directory. Open
up this directory and search for Refprop.dll.
If you find it, delete it (it should never be stored in the Windows
directory). The new one belongs only the
Refprop directory along with the executable.
If the following error message appears when the graphical interface is
launched:
run-time error 339
component
MSHFLXGD.OCX or one of its dependencies not correctly registered:
a file is missing or invalid
then check to see if you have a firewall or antivirus software that can
be turned off. Deactivating these will often allow successful installs,
especially on Vista machines. If this fails or is not an option, then
download the file from the link below and save it in your Windows\System32 or
Windows\System directory.
MSHFLXGD.OCX
In some cases where you are not allowed to be the administrator on a machine,
this message will appear because it cannot access the System32 directory. Try placing the file in your Windows
directory to get the program to work.
The comdlg32.ocx file may also sometimes be needed:
COMDLG32.OCX
If an error message occurs referencing the file REFPROP.MSI, try the
following: Press your Start button, and
then click on "Run …". Type in
Regedit. If it does not start at the top
of registry, scroll to the top and click on "My Computer". Search for "Refprop 8.1.msi", or
whatever msi file it is complaining about in the install error message. You should find something like
"HKEY_CLASSES_ROOT\ Installer\ Products\
6398724E8B370524FA88122E26945D8F".
For every occurrence of the item in the registry, you should either
rename or delete it. To rename, simply
add an underscore in the sequence of numbers, such as
"_6398724…". Then try
reinstalling the program.
Help
File. The most recent help file from Refprop is available
below. You should download it to your
machine before launching it, otherwise the help file will appear blank.
REFPROP.CHM
For users of the EditPad editor from JGSOFT, a
scheme is available to highlight the .fld and .mix files. This scheme was
written by Bruce Wernick, and can be downloaded from http://www.just-great-software.com.
HFC-1234yf and HFC-1234ze. Equations of state are now available for
these two fluids. The fluid files are
located below and should be placed in your Refprop\Fluids directory. The fluid files included in version 9.0
incorrectly used the NBP reference state.
R1234yf.fld
(uploaded June 6, 2012 with updated transport equations)
R1234ze.fld
(uploaded June 6, 2012 with new CAS number and updated transport equations)
Humid Air. Although version 9.0 allows mixtures of nitrogen, argon, oxygen, and water as a consequence from the addition of the new natural gas mixture model, calculations for moist air have not been tested yet. It is likely that calculated values are reasonable, however, Refprop may not return results because the saturation routines may fail. The program calls the saturation routines to determine if the state is vapor, liquid, or two-phase. If you know that your state point is in the vapor phase, you can avoid the call to the saturation routines by using TPRHO instead of TPFLSH. The Fortran file FLSH_SUB.FOR gives additional information concerning the inputs to these routines. In the graphical interface, see the section below on forcing phase calculations. A moist air mixture could be made up starting with the composition of dry air used in Refprop: 0.7812 nitrogen, 0.0092 argon, and 0.2096 oxygen (on a mole basis). A small amount of water could be added to this composition and then normalized.
Transport Properties for Nitrogen, Oxygen, Argon, and
Air. The transport properties for nitrogen, argon, and
oxygen in version 7.0 did not include the thermal conductivity enhancement for
the critical region and did not represent the experimental data as well as
possible. The transport equations for these fluids have been redone and
now represent the data to within their experimental uncertainties. The
publication below documents the new equations and shows all of the comparisons
to data.
N2-Ar-O2
Transport equations documentation
Transport Properties
for Pseudo-pure Fluids, Adding Pure Fluids to a Mixture Setup. The ability to load both a mixture and a
pure fluid not associated with the mixture is now possible with the DLL given
above (under the Updates section). For
example, a natural gas mixture of methane, ethane, and propane could be loaded,
along with R134a, which is not part of the mixture. By calling SETNC and PUREFLD, properties for
either the mixture or the pure fluid can be made without ever calling SETUP
more than once at the beginning. This is
also useful for calculating transport properties when the pseudo-pure fluid
equation of state is in use (for R-404A, R-407C, R-410A, and R-507A). Since transport properties are not available
in the PPF files, the full mixture has to be loaded as well. The example program below gives all the
details.
PPF-EX.FOR
Solids. The REFPROP program does not know the location
of the solid-liquid interface for a mixture. For many of the pure
fluids, melting line auxiliary equations are available and can be used to
calculate liquid properties at the point where solids begin to form and can be
used to keep the program from entering the solid phase. When melting
lines are not available, the program uses the liquid phase density at the
triple point as the maximum density, thus valid states between this density and
the melting line will not be available. The location of the solid-liquid
boundary can be calculated under the Calculate/Saturation Tables option.
This option will also print out the vapor phase properties along the
sublimation line if requested (and if an auxiliary equation is available).
Defining Two-Phase States for Pure Fluids.
Defining the state of a fluid normally requires two inputs, such as
pressure-temperature, temperature-enthalpy, pressure-enthalpy, and so
forth. This is true for the single-phase
states and for two-phase solutions with mixtures of fluids. (Some inputs may have two solutions,
this was described earlier.) For pure
fluids, using inputs of pressure and temperature is not sufficient to describe
the state of the fluid since both remain constant between the liquid and vapor
states. Some other property, such as
quality, enthalpy, or density, is required to specify the two-phase state point
for the pure fluid. Once the quality is
known, some of the other thermodynamic properties can be calculated with the
equation M=q*Mvap + (1-q)*Mliq,
where M is the property of interest
and q is the quality. There are several properties that cannot be
calculated this way, including the heat capacities, the speed of sound, and the
transport properties. These quantities
are undefined in the two-phase region for any fluid, except Cv, which is defined very differently
than one would expect. There are some
people who use a different formula to calculate the speed of sound in the two
phase, but it is applicable only in certain specific applications. In these situations, it is best to consider
the properties of the liquid and of the vapor separately, and how they interact
with the application being developed.
As an example, consider Cp, which could be calculated from any
equation of state using the quality, but thermodynamically is not defined for a
two-phase mixture. Cp is the
heat capacity along an isobaric process and is equal to dH/dT. Since pressure and temperature do not change
across the two phase for a pure fluid, then that means Cp would be equal to infinity because the heat capacity changes but
the temperature does not, thus the definition makes it thermodynamically
impossible to calculate it. The only place that Cp can be infinity is at the critical point.
Multiple and Metastable States. There are cases where an input state point can result in two separate valid states. The most common is temperature-enthalpy inputs. Viewing a P-H diagram (or a T-H diagram with very high pressures) will help show how there can be two valid states points for a given input. For example, nitrogen at 140 K and 1000 J/mol can exist at 6.85 MPa and at 60.87 MPa. When this situation occurs, Refprop returns the state with the higher density. For these state points , the character '<' or '>' can be added to the number (before or after) to find the lower or upper root, respectively. In the Excel sample file, the use of these characters was added after the release of version 8.0; the new example file REFPROP.XLS (given below in the Excel section) contains new code and an example of its use. These same characters can also be used to find metastable fluid states for temperature and pressure inputs. For example, the saturation pressure for nitrogen at 100 K is 0.778 MPa. Inputs of 100 K and 0.777 MPa will return a vapor state, but inputs of '100' for temperature and '0.777>' for pressure will return a metastable liquid state. See below for additional information about the use of the '>' and '<' symbols.
FLSH Routines and Metastable States.
For subroutines such as ENTHAL, ENTRO, CVCP, etc., where temperature and density
are the input properties, the output property data will differ from those
returned when using routines such as PHFLSH or TPFLSH when in the two-phase
region. Any routine (except TDFLSH) that
uses temperature and density as inputs will return what appears to be erroneous
results in the two-phase region. These results actually show
calculations directly from the equation of state without taking into account
the fact that the mixture has split into two phases. The results would be
valid for such situations where a substance is heated beyond its boiling point
(a metastable state), but without boiling (such as water in a glass container
being heated in a microwave). The results eventually end up at the
spinodal, beyond which it is no longer possible to increase the temperature
without boiling the liquid. Thus, for typical results these routines
should never be used for two-phase calculations, rather the FLSH routines
should be called. The flash routines return the properties in the liquid
and vapor states, and these can be used to call routines such as THERM, CVCP,
TRNPRP, etc., with the associated liquid or vapor density at the saturated
temperature.
Convergence Failures and Forcing Phase Calculations. When using mixtures, error messages will sometimes be reported when Refprop fails to converge during an iteration, usually during the calculation of a VLE state close to the critical point. In some situations you may know that the point is in the single phase and wish to force the calculation in spite of the error message. This can be done with the '>' and '<' symbols. When one of these is attached to a number in the Specified State Points table, Refprop will assume that the point is in the liquid phase when '>' is attached and in the vapor phase when '<' is attached. Care must be taken because metastable states will be returned in the point is in the two phase. When a state point is above the critical point but Refprop reports a nonconvergence, you can use either of these symbols to force the calculation. For example, a 0.5/0.5 mixture of methane/propane will report a nonconvergence at 300 K and 10 MPa. A P-rho diagram shows that the point is above the critical pressure. Entering '300' for temperature and '10>' for pressure will return the valid state point at 10.826 mol/l.
Mixture Error Messages. The error message "No mixture data are available for one or more binary pairs in the specified mixture. The mixing parameters have been estimated." (message #117) occurs when an interaction parameter for two different fluids is not available in the program. The most common reason for this occurrence is a lack of experimental data to describe VLE, densities, and so forth for the binary pair. In other situations, such as many mixtures with water, interaction parameters have not been fitted to the REFPROP model even though data exist. An estimation scheme is available in the program to approximate one of the interaction parameters that helps improve bubble and dew point pressures. This error message indicates that you should be aware that calculated properties are estimates only. For similar fluids, especially among the refrigerants, the scheme works fairly well. It breaks down with dissimilar fluids and eventually the scheme will produce large interaction parameters and will report the error message "No mixture data are available for one or more binary pairs in the specified mixture. The mixture is outside the range of the model and calculations will not be made."
.NET
Applications. The following simple application can be used
to link Refprop with VB.NET:
REFPROP.VB
Other Refprop users have also submitted different wrappers for .NET and C applications and they have each given us
permission to distribute their code.
.NET and C applications by Craig Fennessy (of
Cryogenic Industries)
FENNESSY.ZIP
.NET applications in visual basic (VB2008) by
Ismail Alkan (of Foster Wheeler North America Corp.)
ALKAN.ZIP
VB2008 sample code by Letizia Conter (of S.E.I.C. srl).
CONTER.ZIP
C
Applications. A sample C++ file comes with the Refprop
program and is installed in the Examples directory and explained in the help
file. An example for the C programming
language has been written by Ian Bell and he has
given us permission to distribute his code to others. The zip file is included
below:
C.ZIP
Mixture Files. The Fortran code and Excel sample file in version 7.0 are not able to read the *.mix files, but that has changed in version 8.0. However, the .mix files are ASCII files and thus can be read from any editor and are quite simple to understand. The first two lines are just information and can be ignored.
Required Fluids for Distribution. There are several fluid files that Refprop
accesses in order to run properly. These are nitrogen.fld, propane.fld,
R134a.fld, and C12.fld (dodecane). These fluids are used as reference
fluids in extended corresponding states methods employed in Refprop to predict
transport properties for some instances. These fluids (and the hmx.bnc
file) should be distributed in addition to those required in a particular
application if the Refprop routines have been incorporated into a software package.
CAPE-OPEN Applications.
The following weblink gives the details of a third-party application for
linking Refprop to CAPE-OPEN applications.
http://www.amsterchem.com/refpropco.html
Python Applications. Two example files for the Python
programming language have been written by Bruce
Wernick, and he has given us permission to distribute his code to others.
The applications are included below:
WERNICK.ZIP
Ben Thelen of Leukothea Pte. Ltd. has updated these files and made them
available:
THELEN.ZIP
Perl Applications. The following example file for the Perl
programming language has been written by Chermac Rolle, and he has given us
permission to distribute his code to others.
PERL.ZIP
MatLab
Applications. Keith
Wait from GE Home Business Solutions has made the following MatLab application
available. This application calls the
Refprop DLL directly rather than through the mex file provided in previous
versions of Refprop. These files will
replace the older files once enough testing has been done to ensure that full
compatibility still exits with 32 and 64 bit applications. This
release now includes the molar mass, compressibility factor, gross and net
heating values, critical point properties, volumetric expansivity, and a number
of other properties. The routines can
now read mixture files (*.mix). When
using these new files, be sure to delete the old refpropm.mexw32 or
refpropm.mexw64 files if you downloaded them previously.
refpropm.m
(uploaded Dec. 13, 2012)
rp_proto.m
rp_proto64.m
Note:
These file names are now lowercase, if you downloaded uppercase
versions, delete them before
downloading otherwise the case will be changed and the files will not work.
LabView Applications. A LabView application has been written by
Greg Sussman and substantially expanded by Yan Ding. The application is given below:
LABVIEW.ZIP
Excel
Applications. To make the Excel routines in Refprop
available to any worksheet, two environment variables called RPprefix and Path
should be added in a similar manner as shown below in the User variables
section:
In 64-bit versions of Windows,
Microsoft added another Program Files directory called "Program Files
(x86)", which is the default directory where Refprop gets installed. For the connections to work, you need to
either point to this directory in your path statement or copy all the Refprop
files to the old "Program Files" directory.
Do not add these to your System variables section (and more importantly, do NOT
damage your path statement in the System variables section!). In XP, the environment variables can be set
under Start/Settings/Control Panel/System/Advanced/Environment Variables, under
the "User variables" option.
In Windows 7, this can be found in Start/Control Panel/System And
Security/System/Change settings/Advanced/Environment variables.
In some cases where Excel cannot find the Refprop fluid files, you can
copy the *.FLD and HMX.BNC files into a default directory. This directory can be located on either the
C:\ or D:\ drives. If you work on C:,
make a new directory within the root of that drive called C:\REFPROP\FLUIDS. Copy the FLD and BNC files into this
directory. When the program fails to
find the fluid files, it will look to see if a C:\REFPROP\FLUIDS (or D:) is
available, and if so it will use the files from that source.
Excel 2007 appears to have a
"feature" that is not in the 2003 version. In the older version, the following is
allowed:
=Pressure("water",
"TVAP", "SI", 298)
This results in a #VALUE! in the newer version. Excel 2007 may require the comma for the
missing parameter:
=Pressure("water",
"TVAP", "SI", 298,)
The property quality in version 7 and 8 was assumed to always be given
on a molar basis, even though it was labeled as on a mass basis when mass units
were in effect (this only affects mixture calculations). The file has been fixed and the latest
version is available below, along with many other updates. This file also contains the new subroutine
FluidString that replaces the Concatenate command making it much easier to set
up mixtures. The latest version now
contains code that does not call Setup if the compositions have changed, but
not the fluid names, increasing calculation speed for mixtures with varying
composition.
Refprop.xls
(last updated Feb. 13, 2013)
In some cases the macros may not work.
Try saving the file as a macro-enabled workbook (under Save As…).
The xls file distributed with version 9 sometimes will give false answers
depending on the sequence of calculations if multiple xls files are open. Switching between the open files may cause
the initial setup to be lost. The
updated xls file given above fixes this.
The following steps may help if the spreadsheet is still not working:
1. Open REFPROP.xls and save it as an
add-in, REFPROP.xla or REFPROP.xlam, in the main REFPROP folder, C:\Program
Files\REFPROP.
2. Go to File/Options/Trust Center/Trust
Center Settings (button at bottom right).
3. Select "Trusted Locations"
on the left. Click "Add new location". Browse to
C:\Program Files\REFPROP, select "Subfolders of this location are also
trusted", and click "OK".
4. Go to File/Options/Add-Ins and select
"Excel Add-ins" in the Manage drop-down box at the bottom, and click
Go.
5. Click "Browse", and navigate
to C:\Program Files\REFPROP, select REFPROP.xlam and click OK. IMPORTANT:
Do not simply select REFPROP.xlam when it first comes up, as this will be in
the wrong folder (C:\Documents and Settings\Username\Application
Data\Microsoft\AddIns), which is not trusted and will not work.
6. Select the Data tab, and click on
Edit Links. Select REFPROP.xlam. Click on Change Source and
navigate to C:\Program Files\REFPROP. Select REFPROP.xlam there and click
OK. (This is just to make sure you are connected to the correct Add-in.)
7. Once you have the xla or xlam file set
up, you can open a brand new work book and the functions should be available to
you. Do not continue working with the
Refprop.xls file since it still contains the VB code that is also in the xlam
file. In this manner, future updates from
NIST of the Refprop.xls file can be resaved as the xlam file, and all of your work
books will have access to the most recent code.
For 64-bit Office 2010, please
contact Eric Lemmon to obtain a 64 bit DLL.
Please send questions to Eric Lemmon: Eric.Lemmon@NIST.gov
«(If
you send a question and do not receive a response within several days, it is quite
likely that your email did not make it or that my email was removed by your
system administrators as spam or junk mail.
I try to respond to all emails within two days, so please write/call
again if you do not receive a response.)
Last modified: Feb. 13, 2013.