SteamTablesIIE: An ActiveX to Calculate the Thermodynamic Properties of Water

Abstract

The thermodynamic properties of water are of fundamental importance to perform geochemical, reservoir and production engineering calculations in the geothermal industry. Using the IAPWS-95 formulation an ActiveX component, SteamTablesIIE is developed to calculate thermodynamic properties of pure water as a function of two independent intensive variables: (1) temperature (T) or pressure (P) and (2) T, P, volume (V), internal energy (U), enthalpy (H), entropy (S) or Gibbs free energy (G). The second variable cannot be same as variable 1. Additionally, it calculates the properties along the separation boundaries (i.e., sublimation, saturation, critical isochor, ice I melting, ice III to ice VII melting and minimum volume curves) considering the input parameter as T or P for the variable 1.

SteamTablesIIE takes into account the following 27 intensive properties: T, P, fraction, state, V, density (Den), compressibility factor (Z0), U, H, G, Helmholtz free energy (A), S, heat capacity at constant pressure (Cp), heat capacity at constant volume (Cv), coefficient of thermal expansion (CTE), isothermal compressibility (Ziso), speed of sound (VelS), partial derivative of P with T at constant V (dPdT), partial derivative of T with V at constant P (dTdV), partial derivative of V with P at constant T (dVdP), Joule-Thomson coefficient (JTC), isothermal throttling coefficient (IJTC), viscosity (Vis), thermal conductivity (ThrmCond), surface tension (SurfTen), Prandtl number (PrdNum) and dielectric constant (DielCons). The use of SteamTablesIIE requires certain precautions because there may be multiple values.