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Eric W. Lemmon (Fed)

Mechanical Engineer

Dr. Lemmon received his Ph.D. at the University of Idaho in 1996. The dissertation introduced a new Helmholtz energy model for mixtures of hydrocarbons, cryogens, and refrigerants based on a generalized excess Helmholtz energy concept. His current work focuses on the Refprop program ( and on national and international standards for the properties of natural gas.

Google Scholar Citation Page(link is external)

Research Interests:

He is the chair of the ISO committee that will publish the next standard for the nist-equation of state for these mixtures. Dr. Lemmon has developed many nist-equations of state and a new nonlinear fitting technique that allows operations that are not available in linear methods. This has resulted in much smaller nist-equations that extrapolate without limits in all directions.

Selected Publications


Fundamental Equation of State for Fluid Tetrahydrofuran

Felix Fiedler, Joel Karog, Eric W. Lemmon, Monika Thol
An empirical equation of state in terms of the Helmholtz energy for tetrahydro- furan is presented. In the validity range from the triple-point temperature up

An Equation of State for the Thermodynamic Properties of Helium

Diego Ortiz Vega, Kenneth Hall, James Holste, Allan H. Harvey, Eric W. Lemmon
This report documents the equation of state for fluid helium implemented in Version 10 of NIST's REFPROP Standard Reference Database. The equation of state is
Created October 9, 2019, Updated December 8, 2022