Calculates properties for over 100 pure fluids. Mixtures: Models complex mixtures with up to 20 components.
: It calculates thermodynamic properties (density, enthalpy, entropy) and transport properties (viscosity, thermal conductivity) for pure fluids and mixtures.
Introduction to NIST REFPROP 9 Accurate thermophysical property data is critical for engineering design, chemical processing, and scientific research. The National Institute of Standards and Technology (NIST) Reference Fluid Thermodynamic and Transport Properties Database (REFPROP) is the global gold standard for this data. Version 9 remains a widely used, industry-accepted release of this software. It provides highly precise calculations for complex fluid mixtures and pure fluids. Engineers rely on it to simulate cycles, design equipment, and optimize chemical processes. What is NIST REFPROP 9?
Pressure, temperature, density, enthalpy, entropy, heat capacity, and speed of sound. Transport: Viscosity, thermal conductivity, and surface tension. Phase Equilibrium:
| Problem | Solution | |---------|----------| | "Fluid not found" | Check fluid name spelling (e.g., R134a not 134a ). Use Fluids → List . | | Mixture phase error | Ensure T,P are within envelope; use Calculate → Phase boundary first. | | DLL not loading in Python | Run 32-bit Python, set working directory to REFPROP folder. | | Plot window blank | Save data to .txt first, then plot in Excel/origin. | | License error | Reinstall refprop.lic ; ensure path has no spaces. | nist refprop 9
Surface tension (for pure fluids at the liquid-vapor interface). Underlying Theoretical Models
: Calculates essential data including density, entropy, enthalpy, and compressibility factors .
REFPROP v9 calculates pseudo-critical points , dew/bubble curves, and phase boundaries.
For the most critical pure fluids, REFPROP 9 utilizes wide-range equations of state explicit in Helmholtz energy. These equations are empirical formulations based on thousands of high-precision experimental data points. They map out fluid behavior from the triple point up to temperatures of several thousand Kelvin and pressures reaching into the gigapascals. Mixing Rules and Interaction Parameters Calculates properties for over 100 pure fluids
REFPROP 9 includes highly accurate formulations for over 100 pure fluids, categorizing them into:
For version 9.1, NIST added or significantly modified the thermal conductivity and/or viscosity equations for hydrogen, parahydrogen, toluene, RE-347mcc, SF₆, benzene, and several siloxanes, ensuring state-of-the-art accuracy for these parameters.
The reliability of REFPROP 9 stems from its implementation of highly accurate mathematical models.
His fingers hovered over the keyboard. On his screen was an icon as old as the space program itself: a little green flask labeled . It provides highly precise calculations for complex fluid
The true measure of NIST REFPROP 9.0’s success lies in its adoption as a de facto industry standard. In the HVAC&R (Heating, Ventilation, Air Conditioning, and Refrigeration) industry, safety standards such as ASHRAE 34 and the AHRI (Air-Conditioning, Heating, and Refrigeration Institute) performance rating standards explicitly require the use of REFPROP for calculating fluid properties for rating equipment.
: Serving as a reference library for mass flow meters and controllers to allow field adjustments for different gas types.
The high accuracy of REFPROP 9 stems from its reliance on advanced, peer-reviewed mathematical formulations. Equations of State (EOS)