#Welcome to REFPROP2Modelica! This piece of software enables the user to access the Refprop fluid property database from within Modelica. Even though the code base is not very mature yet, this package seems to be the only solution to access properties of mixtures from within Modelica on both Windows and Linux systems. The aim is to develop wrapper classes and integrate them with the Media framework inside Modelica. It has only been tested with Dymola so far.

Installation Instructions

You can use the provided makefiles to compile and install the wrapper. The process should be straightforward. You can get the latest release from https://github.com/jowr/REFPROP2Modelica/releases

Windows

Since I do not run Windows regularly, I am not able to test many things myself. Could you, dear Windows users, please provide me with feedback?

1. After downloading, unpack and rename the folder to REFPROP2Modelica.
2. Open _wrapper\Makefile.bat with a text editor and edit line 23 and 24 according to your system (Dymola 2013 FD01, Dymola 2014 or ...).
3. Run _wrapper\Makefile.bat from your Visual Studio console, tested with VS 2008 and VS 2010 Express.
4. Make sure to have the shared library refprop.dll available on your system. This can be done by going to (Right click)Computer > Properties > Advanced system settings > Environment Variables. In the bottom half of the window (called System variables), select 'Path' and click 'Edit...'. This will open a new window called Edit System Variable'. Add the REFPROP directory path with a leading semicolon at the end in 'Variable value'. This directory path could be, e.g., C:\Program Files\REFPROP\ or C:\Program Files (x86)\REFPROP depending on your operating system.
5. Set the path to the REFPROP program directory with the constant String REFPROP_PATH (at the beginning of the Modelica package). Make sure you mask the backslashes. It should look something like: constant String REFPROP_PATH = "C:\\Program Files\\REFPROP\\"; or constant String REFPROP_PATH = "C:\\Program Files (x86)\\REFPROP\\";

Linux

For installing on a Linux machine, please follow these instructions

1. After downloading, unpack and rename the folder to REFPROP2Modelica.
2. Open a command prompt in _wrapper, then run make all and sudo make install.
3. Make sure to have the shared library librefprop.so available on your system. You might want to check https://github.com/jowr/librefprop.so for details.
4. Set the path to the REFPROP program directory with the constant String REFPROP_PATH (at the beginning of the Modelica package). It should look something like: constant String REFPROP_PATH = "/opt/refprop/";
5. If you experience problems with older versions of this package, you can run sudo make fixit to create additonal aliases. This compiles and installs a dynamic library on your system.
6. ... and finally to remove the files from your system, please use sudo make uninstall.

General Remarks

Please note that you need a working and licensed copy of Refprop in order to use the software provided here. This is not a replacement for Refprop, only a wrapper to use it with Modelica.

Links

If you are interested in this kind of software, you might also want to consider the following projects:

1. https://github.com/Heineken/REFPROP2Modelica (The original version of this library)
2. https://github.com/thorade/HelmholtzMedia (A Modelica implementation the Helmholtz functions)
3. http://coolprop.sourceforge.net/ (A free fluid property library also based on Helmholtz formulation)

Usage notes on partial derivatives

There are four ways to compute partial derivatives determined by "partialDersInputChoice", an input the setState_phX() and setState_pTX() functions:

1: none (default)

2: partial derivatives of d wrt p,h,X In two-phase region: numerical differentiation for all derivatives In single phase region: dddX is numerical and others are analytical

3: partial derivatives of d wrt p,h,X In two-phase region: pseudo analytical (similar procedure as pure fluid - they give almost same result as method 2, and with less CPU effort). In single phase region: dddX is numerical and others are analytical

4: partial derivatives of d and h wrt p,T,X In two-phase region: numerical differentiation for all derivatives In single phase region: dddX is numerical and others are analytical

The second and fourth methods compare exactly with stepping forward in u,d,X (the baseline with most CPU effort, due to tedious iteration in property functions at every time step, u,d,X -> T,p,h etc.). Method 4 is guicker in the two-phase region compared to method 2, because T and P are equilibrium quantities, and thus the most typical flash function.. Method 3 is fastest, but does not give correct dynamics and will cause mass convervation to fail.

Note that the dddX derivative is the difference in dddX1|X2=const-dddX2|X1=const

The partials works only for binary mixtures and have only been tested for NH3/water.. See tester package..