.MultiPhaseMixture.Information.ExternalPropertyPackages.RefProp

Information

RefProp (NIST Reference Fluid Thermodynamic and Transport Properties Database ) is a commerical program for calculation of thermodynamic and transport properties. It's developed and maintained by the National Institute of Standards and Technology. RefProp contains high accuracy models of industrially-important fluids (the equations are the most accurate equations available worldwide [2]). The high accuracy is achieved by using high order polynominals which also makes them more computational demanding than a cubic equation of state as e.g. Redlich-Kwong or Peng Robinson.

Tool Requirements

• Compiler: Visual studio 2010 or later
• Dymola 2015 or later

Refprop version

The newest version of RefProp 9.1.1 should be used.

RefProp 9.1 can be updated from http://www.boulder.nist.gov/div838/theory/refprop/911-1/REFPROP.HTM

NOTE: Using RefProp 9.1 instead of RefProp 9.1.1 can lead to non-deterministic behaviour wrt to when a flash calculation can be solved or not.

Modelica Settings

Settings in MultiPhaseMixture.Templates.ExternalTwoPhaseMixture that should be used when creating a new Fluid.

• nP=2, the number of supported phases by RefProp is always 2
• libraryName="RefProp"

Specific RefProp setup information is set in the setupInfo string. Different options are separated by the | delimiter.

Supported options in setupInfo:

• path= path to RefProp installation, e.g. path=C:/Program Files (x86)/REFPROP/
• mixture=name of mixture file, e.g. mixture=air.mix , if no mixture file is specified it's assumed that the fluid is pure and that the compound is specified in compounds
• eos= equation of state, supported options default or PengRobinson, e.g. eos=PengRobinson or eos=default

Example - DryAir mixture medium

See MultiPhaseMixture.PreDefined.Mixtures.RefProp.DryAir

Limitations

• For the general flash routines there is no possibility to provide start values. I.e the caching is not implemented for the RefProp backend.
• RefProp does not seem to be suited to be used for larger system simulations for mixtures due to the disadvantages mentioned in chapter 4.4 (Windahl, 2015) and that it by default use highly precise multi-parameter equation of state which is rarely used for mixtures due to the computational effort (Schultze, 2014). To overcome these limitations further analysis is needed.

References

1. Lemmon, E.W., Huber, M.L., McLinden, M.O.  NIST Standard Reference Database 23:  Reference Fluid Thermodynamic and Transport Properties-REFPROP, Version 9.1, National Institute of Standards and Technology, Standard Reference Data Program, Gaithersburg, 2013.
2. http://www.boulder.nist.gov/div838/theory/refprop/Frequently_asked_questions.html
3. C. Schultze, A Contribution to Numerically Efficient Modelling of Thermodynamic Systems, PhD thesis, Technische Universität Braunschweig, Fakultät für Maschinenbau., (2014)
4. Johan Windahl, Katrin Prölss, Maarten Bosmans, Hubertus Tummescheit, Eli van Es, Awin Sewgobind: MultiComponentMultiPhase - a framework for thermodynamic properties in Modelica Modelica 2015 Conference, Palais des Congrès Versailles, France, Sep. 21-23, 2015.