The Legacy API calls were introduced in NIST REFPROP 9.1.1 through a single DLL and wrappers for these functions are introduced in the RefProp Mathcad Add-in version 2.0. These property functions follow a standard nomenclature with
- All functions beginning with the characters rp_ to avoid conflict with any other functions
- The prefix is followed by the property being calculated (e.g. rho, h, s, cp, w, etc.)
- The property symbol is followed by a phase character if along the saturated liquid (f) curve or saturated vapor (g) curve.
- The phase character is followed by a single state point property code (e.g. t or p) or a state point pair if no phase character is present for liquid, vapor, or two-phase conditions (e.g. tp, ts, th, ps, ph, etc.)
For example, the calculation of enthalpy, h, as a function of temperature and pressure
Listing of the many individual Legacy API Custom Function wrappers is not provided here, but can be found in the RefProp Legacy API Help
By far, the best way to use the Legacy API functions is through the user functions provided in the Refprop_units.mcdx include worksheet. These functions have the following benefits:
- Function names are more intuitive and follow standard thermodynamic nomenclature, including greek symbols
- These functions handle input parameters with Mathcad units and apply units to the return values automatically.
Users should examine the Refprop_units.mcdx include worksheet for the further details of the functions and their use.
A brief example of the usage of the Legacy API Custom functions through the user functions provided in the Refprop_units.mcdx include worksheet are shown below.
