REFPROP (REFriference Fluid PROPerties) is a computational database developed by NIST to provide highly accurate thermophysical properties for industrially important fluids and their mixtures. It has become the global standard for the refrigeration, natural gas, and aerospace industries because it implements the most precise models available, primarily based on Helmholtz energy equations of state. These models ensure thermodynamic consistency across gas, liquid, and supercritical states. Differences Between Versions
The "free" versions found on the internet often fall into two categories:
Overjoyed, Alex downloaded and installed REFPROP 91. He was amazed by the new features and the improved accuracy of the software. He began to work on his project, using REFPROP 91 to model the thermodynamic properties of the new refrigerant.
Searching for "REFPROP 9.1 free download" often leads to untrusted websites. These downloads may contain malware, viruses, or outdated data files that do not provide the accuracy promised by official NIST data. refprop 91 free
If you are a student, check if your or engineering department already holds a site license. Many academic institutions provide access to the full version of REFPROP 10.0 for research purposes at no cost to the student.
NIST maintains REFPROP as a commercial product. As of the last pricing models, a single-user license for REFPROP costs several hundred dollars (around $325–$500 depending on the version and institutional discounts). A site license can cost thousands.
The current version (10.0 or 11.0) has more features, but 9.1 remains popular because older hardware can run it and legacy tutorials reference it. Differences Between Versions The "free" versions found on
If you require more capabilities than mini-REFPROP but cannot afford the full NIST software, is the best professional-grade, open-source alternative. In fact, many official NIST wrappers and community tools are built to interface with CoolProp as a free alternative to REFPROP. It is a cross-platform, open-source library that provides thermodynamic and transport properties for a vast array of fluids using reference-accuracy equations of state. CoolProp can be a fantastic, free choice for many applications, though for critical industrial or academic work requiring the absolute highest accuracy and convergence stability for all fluids, the full NIST REFPROP remains the gold standard.
: Version 9.1 has officially been superseded by REFPROP Version 10.0 . Pirated distributions often use corrupted or legacy equation files that introduce mathematical anomalies. Official Free Options: Mini-REFPROP
While the full standard version of REFPROP Version 9.1 requires a commercial license, students, engineers, and researchers can utilize legitimate to perform high-accuracy fluid thermodynamic calculations legally. 1. What is REFPROP 9.1? Searching for "REFPROP 9
: It supports 105 pure fluids and mixtures with up to 20 components, including refrigerants (HFCs, CFCs), natural gases, and cryogens. Integration
T_sat = CP.PropsSI('T', 'P', 101325, 'Q', 0, 'Water') print(f"The saturation temperature of water at 101.325 kPa is T_sat - 273.15:.2f °C")
REFPROP 9.1 represents a significant milestone in the software's history. Released prior to the major interface overhaul seen in version 10, version 9.1 is often remembered for its robust, albeit utilitarian, interface and its comprehensive database. It utilizes highly accurate equations of state—specifically Helmholtz energy formulations—to calculate properties for a wide range of pure fluids and mixtures.