Instead of hunting for a cracked relic (REFPROP 9.1 from 2014), download today. You will have a modern, free, and legally unassailable tool that does everything REFPROP 9.1 could do – and more.
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.
Fortunately, the thermodynamic community has recognized the need for a free, open-source alternative to REFPROP. That alternative is .
is a proprietary software developed by the National Institute of Standards and Technology (NIST) and is not officially available for free . It is a high-accuracy computational tool used to calculate the thermophysical properties of industrially important fluids and their mixtures. 1. Official Free Version (REFPROP Mini) refprop 91 free
If your project mandates official NIST data, you must purchase a legal license for the current version (REFPROP 10).
REFPROP, developed by the National Institute of Standards and Technology (NIST), is a comprehensive software package that provides detailed property data for refrigerants, including thermodynamic properties, transport properties, and phase equilibrium data. It's essential for engineers and researchers working with fluid dynamics, HVAC (heating, ventilation, and air conditioning), refrigeration, and chemical engineering.
While you may find links claiming “REFPROP 9.1 free,” they are unauthorized copies. For legitimate engineering work, consider using (free, open-source) or purchasing the latest REFPROP from NIST. If you need help setting up CoolProp or using NIST’s free online tools, I’m happy to provide a guide. Instead of hunting for a cracked relic (REFPROP 9
| Software | Pros | Limitations | |----------|------|--------------| | | Open-source, high-accuracy, many fluids, Python/MATLAB/C++/Excel | No official GUI (but third-party ones exist) | | NIST Refprop Online | Free, web-based | Single-phase pure fluids only, no mixtures | | ThermoState (Python) | Simple interface, free | Limited fluids vs. REFPROP | | REFPROP Lite (if released) | Not available | — |
Many users began to speculate about the legitimacy of the free version. Some thought it might be a pirated copy, while others believed it could be a beta version or a demo copy. The mystery surrounding REFPROP 91 Free only grew as more people began to discuss it online.
The REFPROP 9.1 free version offers several key features: As of the last pricing models, a single-user
Supports over 120 pure fluids and a vast array of humid air properties. Cost: 100% free for both commercial and academic use. 2. DWSIM (Open-Source Process Simulator)
While "REFPROP 9.1 free" is a popular search term, the software remains a paid product due to the immense research cost required to maintain its accuracy. For those who cannot afford the NIST license fee, is the most professional and reliable free alternative available today.
CoolProp is widely considered the best open-source alternative and can reproduce most REFPROP results within 0.1% for common fluids.
Is this for an or commercial product design ?