Conference article

Fundamental EoS Implementation for {Water+Ammonia} in Modelica

Leonard Becker
Department of Energy Engineering, Technische Universität Berlin, Germany

José Luis Corrales Ciganda
Department of Energy Engineering, Technische Universität Berlin, Germany

Download articlehttp://dx.doi.org/10.3384/ecp15118647

Published in: Proceedings of the 11th International Modelica Conference, Versailles, France, September 21-23, 2015

Linköping Electronic Conference Proceedings 118:69, s. 647-652

Show more +

Published: 2015-09-18

ISBN: 978-91-7685-955-1

ISSN: 1650-3686 (print), 1650-3740 (online)

Abstract

The implementation of a library for the calculation of thermodynamic properties for the mixture {water + ammonia} based on a fundamental equation of state (EoS) for the Helmholtz free energy is developed and presented. The model uses the formulation of Tillner-Roth and Friend (1998) in order to provide the best available single state thermodynamic data. The calculation of the vapour-liquid equilibrium (VLE) with the aid of the fundamental equation of state is examined. However due to difficulties found under certain pressure and temperature conditions, another method for calculating the VLE had to be used. The problems found included unreliable results and difficulties setting the initial values. Saturation temperature polynomials by Johnson (2001) have been found to be faster and more reliable and have been implemented instead. In result it’s possible to calculate thermophysical properties in single and two-phase region at pressures from the melting point up to 40 MPa.

Keywords

Ammonia + Water; fundamental EOS; thermodynamic properties; Helmholtz energy

References

Modelica Association et al. The modelica standard library - 3.3 revision 1. Online, URL: http://www.modelica.org/, 2014.

I.H. Bell, J. Wronski, S. Quoilin, and V. Lemort. Pure and pseudo-pure fluid thermophysical property evaluation and the open-source thermophysical property library coolprop. Industrial & Engineering Chemistry Research, 53(6):2498–2508, 2014. doi: 10.1021/ie4033999.

F. Carluccio, G. Starace, and C. Bongs. Modeling and simulation of a gas absorption heat pump: Proceedings ishpc 2014, 106. 2014.

D. U. Johnson, W.E. Lear, and S. A. Sherif. Curve Fitting of Ammonia-Water Mixture Properties: An Improvement of Patek and Klomfar’s Ammonia-Water Correlations. PhD thesis, University of Florida, 2001.

EW Lemmon, ML Huber, and MO McLinden. Reference fluid thermodynamic and transport properties-refprop, version 9.1. National Institute of Standards and Technology Standard Reference Database 23, 23, 2013.

H. Olsson, H. H Tummescheit, and H. Elmqvist, editors. Using automatic differentiation for partial derivatives of functions in Modelica, 2005. Citeseer.

J. Patek and J. Klomfar. Simple functions for fast calculations of selected thermodynamic properties of the ammoniawater system. International Journal of Refrigeration, 18 (4):228–234, 1995. ISSN 01407007. doi: 10.1016/0140-7007(95)00006-W.

R. Privat, J.N. Jaubert, and Y. Privat. A simple and unified algorithm to solve fluid phase equilibria using either the gamma–phi or the phi–phi approach for binary and ternary mixtures. Computers and Chemical Engineering, 50:139 – 151, 2013. ISSN 0098-1354.

W. C. Reynolds. Thermodynamic properties in si. graphs, tables and computational equations for forty substances, department of mechanical engineering, 1979.

A. Thorade, M.and Saadat. Helmholtzmedia - a fluid properties library. In Proceedings of the 9th International Modelica Conference. doi, volume 10, page 3384, 2012.

M. Thorade and A. Saadat. Partial derivatives of thermodynamic state properties for dynamic simulation. Environmental Earth Sciences, 70(8):3497–3503, 2013. ISSN 1866-6280.

R. Tillner-Roth and D. G. Friend. A helmholtz free energy formulation of the thermodynamic properties of the mixture {water + ammonia}. Journal of Physical and Chemical Reference Data, 27(1):63–96, 1998a. ISSN 0047-2689.

R. Tillner-Roth and D. G. Friend. Survey and assessment of available measurements on thermodynamic properties of the mixture {water+ ammonia}. Journal of Physical and Chemical Reference Data, 27(1):45–61, 1998b. ISSN 0047-2689.

R. Tillner-Roth, F. Harms-Watzenberg, and H. D. Baehr. Eine neue fundamentalgleichung für ammoniak. DKV TAGUNGSBERICHT, 20:67, 1993. ISSN 0172-8849.

H. Tummescheit. Design and implementation of object-oriented model libraries using modelica. PhD thesis, Lund University, 2002.

W. Wagner and A. Pruß. The iapws formulation 1995 for the thermodynamic properties of ordinary water substance for general and scientific use. Journal of Physical and Chemical Reference Data, 31(2):387–535, 2002. ISSN 0047-2689.

Feng Xu and D.Yogi Goswami. Thermodynamic properties of ammonia–water mixtures for power-cycle applications. Energy, 24(6):525 – 536, 1999. SSN 0360-5442.

B Ziegler and Ch Trepp. Equation of state for ammonia-water mixtures. International Journal of Refrigeration, 7(2):101 – 106, 1984. ISSN 0140-7007.

Citations in Crossref