Background

About the IAPWS

IAPWS (The International Association for the Properties of Water and Steam) is an international non-profit association of national organizations concerned with the properties of water and steam, particularly thermophysical properties, cycle chemistry guidelines, and other aspects of high-temperature steam, water and aqueous mixtures relevant to thermal power cycles and other industrial and scientific applications.

Intended Usage

This formulation (IAPWS-IF97) is recommended for industrial use (primarily the steam power industry) for the calculation of thermodynamic properties of ordinary water in its fluid phases, including vapor-liquid equilibrium. The formulation is a close approximation to the IAPWS-IF95 formulation for general and scientific use, but is designed for much greater computational speed.

Range of Validity

The range of validity is divided into several regions (with close tolerances for consistency at region boundaries), each of which is represented by a different fundamental equation. Appropriate combinations of derivatives from this equation can produce any thermodynamic property desired (density or specific volume, sound speed, heat capacity, enthalpy, entropy, etc.). The formulation is valid from 273.15 K to 1073.15 K at pressures to 100 MPa, and there is a high-temperature region extending to 2273.15 K at pressures to 50 MPa. There is also a separate equation for metastable steam at pressures up to 10 MPa.

Credit

The IAPWS-IF97 implementation used in the module is the open-source Java implementation made available by Hummeling Engineering.

If you're using this module for commercial gain, consider donating through their documentation site.