Nist Refprop 9 -

Core Capabilities

NIST REFPROP 9 (Reference Fluid Thermodynamic and Transport Properties) is a legacy version of a widely used software program designed to provide high-accuracy thermophysical properties of industrially important fluids and their mixtures. While it has been superseded by newer versions like REFPROP 10 , it remains a foundational tool in mechanical engineering and thermodynamics.

• Density and specific volume
• Enthalpy and entropy
• Specific heat capacities
• Thermal conductivity
• Viscosity
• Surface tension
• and more...

NIST REFPROP 9 is more than software; it is a documented standard of measurement. By implementing the most accurate equations of state for industrially relevant fluids, it eliminates guesswork from the design of energy systems, chemical plants, and environmental control systems. While newer versions have expanded the fluid library and improved interface design, REFPROP 9 remains a robust, reliable workhorse. For engineers who demand traceable uncertainty and physical rigor, REFPROP—in any version—is the last word in thermophysical property calculations. nist refprop 9

A. HVAC and Refrigeration System Design

The Scientific Core: Why REFPROP 9 is Accurate

• Properties: Density, enthalpy, entropy, ( C_p ), ( C_v ), speed of sound, viscosity, thermal conductivity, surface tension, vapor pressure, etc.
• Fluids: Over 100 pure fluids (refrigerants, hydrocarbons, water, cryogens, natural gases).
• Mixtures: Up to 20 components with user-defined composition.
• Equations of state: Helmholtz energy formulations (GERG-2008 for mixtures, pure-fluid EOS).