The full version of REFPROP is a paid resource, with pricing typically around $325 for a new license and $125 for an upgrade. mini-REFPROP (Free) REFPROP 9.1/10 (Paid) $0 (Free download) Fluid Count ~10 Fluids (e.g., Water, CO2cap C cap O sub 2 147+ Fluids Purpose Introduction to Thermodynamics Industrial design & Research Support No Technical Support Full NIST Support Interface GUI, Excel, Python, C++, etc.
CoolProp is a free, open-source database that matches REFPROP’s capabilities for most engineering applications.
, nitrogen, oxygen, methane, propane, helium, hydrogen, and dodecane. Limitations
EES is a commercial engineering tool that includes a fluid property library similar to REFPROP. The version allows you to solve small problems and access most fluid properties, though the number of data points is limited.
If you only need data for a single fluid at specific points (like the boiling point of R134a at a certain pressure), you can use the . It is free to use online. It uses the same underlying equations as REFPROP. refprop 91 free
If your project mandates official NIST data, you must purchase a legal license for the current version (REFPROP 10).
Both Mini-REFPROP and CoolProp offer Excel add-ins. Once installed, you can call functions directly inside spreadsheet cells (e.g., =PropsSI("D", "T", 298.15, "P", 101325, "Water") ) to automate your engineering calculations without manual data entry. Summary of Options Fluid Selection Best Use Case Comprehensive (100+ fluids + mixtures) Commercial engineering & research Mini-REFPROP Limited (Water, CO2, Methane, etc.) Academic learning & basic tasks NIST WebBook Broad (Browser-based tables) Quick data lookup CoolProp Free / Open-Source Comprehensive (120+ fluids + mixtures) Coding, automation, & Excel work
Engineers, researchers, and students frequently search for a "REFPROP 9.1 free" download. The Reference Fluid Thermodynamic and Transport Properties database (REFPROP), developed by the National Institute of Standards and Technology (NIST), is the industry standard for modeling refrigerant and fluid properties.
For students or researchers on a budget, the mini-REFPROP download provides the core functionality needed for basic thermodynamic calculations without the cost of the full industrial database. The full version of REFPROP is a paid
The REFPROP 9.1 free version offers several key features:
REFPROP (REference Fluid PROPerties) uses highly accurate equations of state to predict fluid behavior across liquid, gas, and supercritical phases. Version 9.1 specifically introduced massive code optimizations, expanded Microsoft Excel integrations, and a catalog containing 121 pure fluids and complex multi-component mixtures.
. Engineers, researchers, and students frequently search for free downloads of this specific legacy version to bypass the $325.00 licensing fee required for the commercial software. While cracked or unauthorized copies violate federal copyright laws and present severe cybersecurity risks, NIST provides official free alternatives—such as mini-REFPROP —alongside powerful open-source substitutes like CoolProp to fulfill the need for free fluid property calculations. Understanding NIST REFPROP 9.1
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. , nitrogen, oxygen, methane, propane, helium, hydrogen, and
To get the most out of RefProp 9.1 free, users can follow these tips and tricks:
The latest version of RefProp, version 9.1, brings significant enhancements and improvements over its predecessors. Some of the key features of RefProp 9.1 include:
REFPROP stands for . It is widely considered the gold standard tool in chemical engineering, HVAC design, aerospace, and mechanical systems. Key Capabilities