A simple formulation for thermodynamic properties of steam from 273 to 523 K, explicit in temperature and pressure

• Published in: International journal of refrigeration 2009-08, Vol.32 (5), p.1123-1125
• Main Authors: Pátek, J., Klomfar, J.
• Format: Article
• Language: English
• Subjects: Absorption system; Applied sciences; Calcul; Calculation; Eau; Eau-bromure de lithium; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Propriété thermodynamique; Refrigerating engineering; Refrigerating engineering. Cryogenics. Food conservation; Système à absorption; Thermodynamic property; Vapeur; Vapour; Water; Water-lithium bromide
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2008.12.010

The present formulation completes the description of the thermodynamic properties of LiBr–H 2O system, the solution properties of which are provided by the previous study of the authors. The intent of the paper is to provide potential users with a simple and easily implementable tool for calculating thermodynamic properties of steam. A Gibss energy equation is presented which was developed as an approximation of the values of the pure water vapor properties computed from the internationally accepted IAPWS formulation 1995. Explicit equations for molar volume, isobaric heat capacity, enthalpy, and entropy are given. The maximum deviations from IAPWS-95 are ±0.03% for molar volume, ±0.8% for isobaric heat capacity, ±0.7 kJ kg −1 (i.e. ±0.026%) for the enthalpy and less than ±0.015 kJ kg −1 K −1 (i.e. ±0.022%) for the entropy. The deviations lie within the declared maximum deviation bands at temperatures from 273 to 523 K and up to the pressure of saturation at each given temperature.