Refprop «2024-2026»

Accurate determination of thermophysical properties is critical for the design, optimization, and safety analysis of chemical processes and energy systems. This paper provides a comprehensive overview of the REFPROP (Reference Fluid Thermodynamic and Transport Properties) database, developed by the National Institute of Standards and Technology (NIST). The discussion covers the underlying mathematical models, including the implementation of the Helmholtz energy equation of state, the vast library of pure components and mixtures, and the software’s capabilities in calculating thermodynamic (density, enthalpy, entropy) and transport (viscosity, thermal conductivity) properties. Furthermore, the paper examines the software’s integration into engineering workflows and its standing as an international benchmark for high-accuracy property calculations.

Historically, engineers relied on generalized correlations (such as the Peng-Robinson or Soave-Redlich-Kwong equations of state) which offer reasonable approximations but often lack precision near the critical point or for complex mixtures. To address the need for a high-accuracy standard, the National Institute of Standards and Technology (NIST) developed REFPROP. This database has evolved into the gold standard for fluid property calculations, providing models that are continuously updated to reflect the latest experimental data and theoretical advancements. refprop

Despite its robustness, users must be aware of certain limitations. REFPROP is optimized for well-characterized fluids. It does not support hypothetical components (e.g., "pseudocomponents" defined solely by boiling point curves often used in refinery modeling) as effectively as process simulators like Aspen HYSYS. Furthermore, the high-accuracy equations are computationally more intensive than simple cubic equations, which may be a factor in large-scale dynamic simulations requiring millions of iterative calculations. This database has evolved into the gold standard