Refprop 91 Free ((top)) -

: Many "free" links are actually for 7-day trials of third-party wrappers (like CAPE-OPEN managers) rather than the NIST engine itself.

REFPROP (Reference Fluid Properties) is the industry standard for calculating the thermodynamic and transport properties of industrially important fluids and their mixtures. refprop 91 free

If you only need saturation properties for pure fluids (not mixtures), the NIST Chemistry WebBook is the official, free source. While it lacks the REFPROP GUI, you can look up: : Many "free" links are actually for 7-day