I was under the impression that any works produced by the government are in the public domain. I also wonder about the legality of the government selling software. I don’t know enough about fluids to estimate the actual cost of development for software like this, but it would stand to reason that a private company would produce a less expensive version if it were possible to be done profitably. While the marginal cost of the software is near zero, there is a substantial, and re-occuring fixed cost from development/support that needs to be recouped.Ģ00$ does seem kind of steep, but I wonder what their over-all volume is, and how that cost would compare to privately developed software of that kind? For my field in EE most software packages cost 10,000$ per license on the low end, up to 50,000$ on the high end. Viscosity and thermal conductivity are modeled with either fluid-specific correlations, an ECS method, or in some cases the friction theory method.I am not sure on their exact reasoning for charging for the software, but it is not too abnormal for government agencies to charge nominal fees to recoup the costs of various services, eg Drivers Licensing. Mixture calculations employ a model that applies mixing rules to the Helmholtz energy of the mixture components it uses a departure function to account for the departure from ideal mixing. It implements three models for the thermodynamic properties of pure fluids: equations of state explicit in Helmholtz energy, the modified Benedict-Webb-Rubin equation of state, and an extended corresponding states (ECS) model. REFPROP is based on the most accurate pure fluid and mixture models currently available. The equations are generally valid over the entire vapor and liquid regions of the fluid, including supercritical states the upper temperature limit is usually near the point of decomposition of the fluid, and the upper pressure (or density) limit is defined by the melting line of the substance. Their high accuracy is obtained through many coefficients in the equations, and thus the calculation speed will be slower than other equations such as the Peng-Robinson cubic equations. These equations are the most accurate equations available worldwide. The program uses equations for the thermodynamic and transport properties to calculate the state points of the fluid or mixture. The REFPROP "database" is actually a program and does not contain any experimental information, aside from the critical and triple points of the pure fluids. REFPROP is a Program, not a Database Containing Measurements. This program, developed by the National Institute of Standards and Technology (NIST), calculates the thermodynamic and transport properties of industrially important fluids and their mixtures. In the thermodynamic module also FLUIDCAL is used by CONVAL ®
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March 2023
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