If you need high-accuracy thermodynamic properties but do not have a budget for REFPROP, consider these open-source options:

Educational tool for students; limited to 11 pure fluids (e.g., Water, CO2, R134a, Nitrogen). Paid ($325)

I understand you're looking for an article on the keyword However, I must start with an important clarification:

Engineering students, HVAC professionals, and chemical researchers frequently search for terms like "REFPROP 10 free download 2021" online. However, because REFPROP is a proprietary database protected by copyright laws, .

: Uses formulation models highly comparable to REFPROP. 2. REFPROP mini Cost : Free. Source : Official NIST offering.

: NIST sometimes provides a "Mini-REFPROP" viewer or limited DLLs for educational use, though these are restricted to a very small number of fluids (usually water, nitrogen, and R134a). Security Warning

If you require the full fluid database for professional research or commercial product development, you should purchase a legitimate license directly via the official Shop NIST Portal. License Type Official Price Individual engineers, researchers, and consultants. Version Upgrade (9.x to 10.x)

If you are looking for a free version of REFPROP 10 for educational or trial purposes, NIST offers a .

If you need the software for professional or academic work, here is how you should acquire it:

Companies and universities can purchase site licenses for multiple users.

CoolProp: The most popular free alternative. It is C++ based, open-source, and integrates seamlessly with Python, MATLAB, and Excel.

REFPROP (NIST Standard Reference Database 23) offers thermophysical properties of pure fluids and mixtures. Version 10 (released in 2018 and updated through 2021) supports over 147 pure fluids and includes:

Reproduce needed correlations from published literature

For single‑point properties (not mixture curves), the NIST WebBook is free and browser‑based. It uses the same underlying REFPROP routines.

. While many sites may use "free download" in their titles to attract traffic, the software must be purchased through official channels to receive a legitimate license. National Institute of Standards and Technology (.gov) Official Licensing & Costs As of 2021, the following official pricing applies for REFPROP 10 at NIST Single User License for new users. for users upgrading from version 9.x to 10.x. Site Licenses : Available for organizations, with discounted pricing starting at 25 users. National Institute of Standards and Technology (.gov) Free "Sample" Version