Nist Refprop Free
Kimbery Challacombe
Excel spreadsheets: A sample spreadsheet is included that demonstrates how the REFPROP DLL can be linked to Excel. Most properties that are available in the graphical interface can also be calculated in the spreadsheet.
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:
For all issues related to ordering the program contact data [at] nist.gov
For questions concerning the installation and running the program, with linking the program with other applications, or with issues concerning the fluid properties, please visit the FAQ site first: -docs/.
Further answers can be found at GitHub: -issues/issues . Please use this site to post new questions as well so that all REFPROP users may learn from the correspondence. If you still need assistance, or have other matters that that you need to discuss, email refprop [at] nist.gov
In addition to this page, further answers can be found at GitHub: REFPROP-issues. Please use the GitHub site to post new bugs or questions so that all REFPROP users may learn from the correspondence. If you still need assistance, or have other matters that you need to discuss, email ref...@nist.gov and we will get back to you as soon as we can.
There are three ways to purchase REFPROP: For your use only, for company wide use, or for use in distribution in your code. These are all explained at If you purchase the program for your use only, the copy you will receive can be installed on all machines that you use (not including servers where others can also access the program). You do not need to purchase a copy for each machine you own.
In some applications where calculations fail after installing versions 9.0 or 9.1, the oldDLL 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 in the Refprop directory along with the executable.
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 corresponding file from the link below and save it in your Windows\System32 directory on 32 bit machines or to your Windows\SysWOW64 directory on 64 bit machines.
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.
If you are feeling brave, you can also try to install REFPROP into the wine environment (a windows-emulation environment). Once you have installed wine (via homebrew on OSX, or via package manager of your linux distribution, google for more information), you can install REFPROP (along with its GUI) into wine with (for instance with REFPROP 10):
Lemmon, E.W., Bell, I.H., Huber, M.L., McLinden, M.O. NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP, Version 10.0, National Institute of Standards and Technology, Standard Reference Data Program, Gaithersburg, 2018.
Additionally, users should cite the reference for either the equation of stateor the transport equations used in their work, for example, if you usedcalculations for CO2, you will find the reference for the equationof state under the Options/Fluid Information option in Refprop and you shouldcite the reference given under that option, like this:
Enhancements have been made to most areas of the NIST REFPROP program, including the equations of state for many of the pure fluids and mixtures, the transport equations, the graphical interface, the Excel spreadsheet, the Fortran files (i.e., core property routines), the sample programs in Python, C++, MATLAB, VB, etc. Some of the more important improvements are listed below:
Several problems in version 9.0 (listed below) were found after its release, and these have all been corrected in 9.1. There are also a few issues with 9.1. If these affect you, please let us know and we will send you the update.
The most recent help file from Refprop is available below. You should download it to yourmachine before launching it, otherwise the help file will appear blank. The PDF is an alternative form of the documentation that may be more convenient for you. The most up-to-date version of the documentation is at -docs.readthedocs.io/en/latest/
The following predefined mixtures are included in the ASHRAE 34 Standard and are supported by REFPROP. In REFPROP 10, many of the predefined mixture files are already included, and additional ones can be generated with the script at -issues/issues/358#issuecomment-872394368
Warning: if interaction parameters are estimated, you should be somewhat skeptical of the model results, and confirm model accuracy against experimental measurements. A good place to start to figure out whether the model might be adequate for your use case, is the survey of measurements and models in
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. 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.
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 at constant p. 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.
Dealing with saturation or 2-phase states in Refprop can be a bit confusing when first using the program. The text and pictures given below address some of these issues to help users better understand how to obtain properties from the program.
Calling SETUP (or SETUPdll) many many times can result in a memory loss error and in a substantial decrease 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.
The calculation of saturation states requires complex algorithms and significant processor time. Version 9.1 introduced the subroutine SATSPLN, which can be called directly after the call to SETUP, and generates spline curves that represent the various properties that are required as initial guesses to the saturation algorithms in order to increase convergence and speed. This new subroutine, however, can take several seconds to implement, and should only be done once at the very beginning. If the composition of the fluid changes significantly, and if you notice problems with convergence, you may need to call it again with the new composition. Although the routine gives estimates only for saturation states, single phase calculations will also be much faster since a call to the saturation routine is required to determine the phase of the input state. The routine is called like this:
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