Mark O. McLinden (Fed)

Dr. McLinden received his BS degree from the University of Missouri-Columbia and MS and PhD degrees from the University of Wisconsin-Madison, all in chemical engineering. He joined what was then the National Bureau of Standards in 1984 and worked in the Thermal Machinery Group of NBS–Gaithersburg, where he developed an equation of state for refrigerant mixtures, carried out analytical studies on the optimum thermodynamic characteristics of refrigerants, and built an experimental apparatus to measure evaporative heat transfer coefficients. He joined the Applied Chemicals and Materials Division of NIST in Boulder in 1988 where his research through the 1990s focused on the properties of alternatives to the ozone-depleting CFC and HCFC refrigerants. His current focus is on highly accurate measurements of fluid properties over wide ranges of temperature and pressure and the design and fabrication of instruments for such measurements. With the current interest in low-GWP alternatives to the HFC refrigerants he has measured several of the “new” HFO refrigerants and led a study that searched for all practical low-GWP replacement fluids. A new research focus is property measurements on gases used in semiconductor processing and the development of three new instruments to carry out those experiments. He is the author or coauthor of more than 125 peer-reviewed publications with 22,000 total citations and an h-factor of 53. He has received several awards related to his research, including a DOC Gold Medal, the J & E Hall Gold Medal of the Institute of Refrigeration (U.K.), and the Yeram S. Touloukian Award of the ASME. When not in the lab, Dr. McLinden enjoys hiking the mountains of Colorado.

Research Areas and Selected Publications

Instrument Development. State-of-the art property measurements have been the hallmark of the Fluid Properties Group for more than five decades. Many of these measurements have been carried out on one-of-a-kind instruments developed at NIST, and Dr. McLinden continues this tradition. He developed, in collaboration with Rubotherm GmbH of Bocum, Germany a two-sinker magnetic suspension densimeter for the measurement of fluid p-r-T (pressure-density-temperature) properties. This instrument applies the Archimedes (bouyancy) principle together with a magnetic suspension coupling to separate the sinkers (sensing elements) from the balance that weighs them to allow measurements over very wide ranges of temperature and pressure (220 K to 505 K, with pressures to 40 MPa). This instrument is one of only a handful of its kind worldwide and is the world’s most accurate instrument for wide-ranging density measurements. In addition to developing the densimeter (which was largely fabricated in the NIST Instrument Shops), Dr. McLinden has advanced this general type of instrument by analyzing the effects of the so-called “force transmision error.” With Dr. Richard Perkins he has developed and put into operation a spherical resonator for the measurement of vapor-phase speed of sound data and a pulse-echo type instrument for liquid-phase speed of sound measurements. A microwave resonant cavity for the measurement of mixture dew points has recently been developed in collaboration with Dr. Perkins of NIST, Prof. Markus Richter of Chemnitz University of Technology (Germany), and Dr. Paul Stanwix of the University of Western Australia. He is also currently pursuing with Drs. Jason Widegren and Christopher Suiter the use of nuclear magnetic resonance (NMR) spectroscopy for the measurement of vapor-liquid equilibria data. A further three instruments are being developed under a CHIPS project on semiconductor process gases:  a dual-capillary viscometer for measurements at the lowest possible uncertainties on inert gases as well as a Greenspan viscometer and cylindrical acoustic resonator for measurements on hazardous gases.

• McLinden, M. O. and Lösch-Will, C. (2007). Apparatus for wide-ranging, high-accuracy fluid (p-r-T) measurements based on a compact two-sinker densimeter. J. Chem. Thermodyn. 39: 507-530. https://doi.org/10.1016/j.jct.2006.09.012
• McLinden, M. O., Kleinrahm, R., and Wagner, W. (2007). Force transmission errors in magnetic suspension densimeters. Int. J. Thermophys. 28: 429-48.  https://doi.org/10.1007/s10765-007-0176-0
• Perkins, R. A.; McLinden, M. O. (2015). Spherical resonator for vapor-phase speed of sound and measurements of 1,1,1,2,2,3,3-heptafluoro-3-methoxypropane (RE347mcc) and trans-1,3,3,3-tetrafluoropropene [R1234ze(E)]. J. Chem. Thermodyn. 91, 43-61. https://doi.org/10.1016/j.jct.2015.07.005
• Suiter, C. L.;  Malavé, V.;  Garboczi, E.; Widegren, J. A.; McLinden, M. O., (2020). Nuclear Magnetic Resonance (NMR) Spectroscopy for the in situ Measurement of Vapor-Liquid Equilibria. J. Chem. Engr. Data 65, 3318-3333. https://doi.org/10.1021/acs.jced.0c00113
• McLinden, M. O.; Perkins, R. A., (2023). A dual-path pulse-echo instrument for speed of sound of liquids and measurements on p-xylene and four halogenated-olefin refrigerants [R1234yf, R1234ze(E), R1233zd(E), and R1336mzz(Z)]. Ind. Eng. Chem. Res. 62 (31), 12381-12406. https://doi.org/10.1021/acs.iecr.3c01720

• McLinden, M. O., Bernardini, L. (2024). A hydrostatic comparator for the density determination of solid objects. Metrologia 62: 025003. https://doi.org/10.1088/1681-7575/adad77

   

Refrigerant Properties. Dr. McLinden has been actively engaged in researching “new” refrigerants for virtually his entire career. This work has included the development of equations of state and other property models and the development of the REFPROP database. He studied the optimum thermodynamic characteristics of refrigerants in relation to the phase-out of the ozone-depleting CFC and HCFC refrigerants in the 1990s, and from 2011 to 2015 he was the Principal Investigator for a major DOE-funded project to search for and evaluate the thermodynamic potential of low-GWP alternatives to the HFC refrigerants. He chaired an International Energy Agency working group, known as Annex 18—Thermophysical Properties of the Environmentally Acceptable Refrigerants from 1990 to 1999; this led to the adoption of international standards for the thermodynamic properties of five of the then-new refrigerants and also facilitated the dissemination of a new approach for the thermodynamic properties of refrigerant mixtures. He served on an ISO Working Group which developed an international standard for refrigerant properties. He serves on several ASHRAE committees concerned with refrigerants. His interests in refrigerants and laboratory work recently intersected with measurements on several new fluorinated-olefin refrigerants, including R1234yf, R1234ze(E), R1233zd(E), and R1336mzz(Z).

• McLinden, M. O.; Didion, D. A. (1987). CFCs:  Quest for Alternatives. ASHRAE J. 29(12): 
  32-42.
• Younglove, B.A. and McLinden, M.O. (1994). An international standard equation-of-state formulation of the thermodynamic properties of refrigerant 123 (2,2-dichloro-1,1,1-trifluoroethane). J. Phys. Chem. Ref. Data  23: 731-779. https://doi.org/10.1063/1.555950
• McLinden, M.O. (1990). Optimum refrigerants for non-ideal cycles:  An analysis employing corresponding states. USNC/IIR–Purdue Refrigeration Conference and ASHRAE-Purdue CFC Conference, W. Lafayette, IN, July 17-20, 69-79. https://docs.lib.purdue.edu/iracc/89/
• McLinden, M.O. and Watanabe, K. (1999). International collaboration on the thermophysical properties of alternative refrigerants: Results of IEA Annex 18. 20th International Congress of Refrigeration, Sydney, Australia, September 19-24, International Institute of Refrigeration, 678-687.
• McLinden, M.O., Klein, S.A. and Perkins, R.A. (2000). An extended corresponding states model for the thermal conductivity of refrigerants and refrigerant mixtures. Int. J. Refrig.  23: 43-63. https://doi.org/10.1016/S0140-7007(99)00024-9
• Richter, M., McLinden, M.O., Lemmon, E.W. (2011). Thermodynamic properties of 2,3,3,3-tetrafluoroprop-1-ene (R1234yf): p-ρ-T measurements and an equation of state. J. Chem. Eng. Data, 56: 3254–3264. https://doi.org/10.1021/je200369m
• McLinden, M. O.; Kazakov, A. F.; Brown, J. S.; Domanski, P. A. (2014). A thermodynamic analysis of refrigerants: Possibilities and tradeoffs for Low-GWP refrigerants. Int. J. Refrig. 38: 80-92. https://doi.org/10.1016/j.ijrefrig.2013.09.032
• Mondejar, M. E.; McLinden, M. O.; Lemmon, E. W. (2015). Thermodynamic properties of trans-1–chloro–3,3,3–trifluoro-propene (R1233zd(E)): Vapor pressure, p-r-T data, speed of sound measurements and equation of state. J. Chem. Engr. Data 60: 2477-2489. https://doi.org/10.1021/acs.jced.5b00348
• McLinden, M. O., J. S. Brown, R. Brignoli, A. F. Kazakov and P. A. Domanski (2017). Limited options for low-global-warming-potential refrigerants. Nat. Comm. 8: 14476. https://doi.org/10.1038/ncomms14476
• McLinden, M. O.; Seeton, C. J.; Pearson, A., (2020). New refrigerants and system configurations for vapor-compression refrigeration. Science 370, 791-796. https://doi.org/10.1126/science.abe3692
• McLinden, M. O.; Huber, M. L., (2020), (R)Evolution of refrigerants. J. Chem. Engr. Data 65, 4176-4193. https://doi.org/10.1021/acs.jced.0c00338
• McLinden, M. O.; Akasaka, R., (2020). Thermodynamic Properties of cis-1,1,1,4,4,4-tetrafluorobutene [R-1336mzz(Z)]:  Vapor pressure, (p, ρ, T) Behavior and Speed of Sound Measurements and Equation of State. J. Chem. Engr. Data 65, 4201-4214. https://doi.org/10.1021/acs.jced.9b01198

• Rowane, A. J.; Rasmussen, E. G.; McLinden, M. O., (2022). Liquid-phase speed of sound and vapor-phase density of difluoromethane. J. Chem. Engr. Data 67, 3022-3032. https://doi.org/10.1021/acs.jced.2c00441

   

REFPROP. The NIST REFPROP Standard Reference Database https://www.nist.gov/srd/refprop  provides properties for a wide variety of industrially important fluids. It is the de facto industry standard for the properties of refrigerants and is increasingly used in the natural gas and chemical process industries. It is one of the main technology transfer mechanisms for the outputs of the Applied Chemicals and Materials Division. The various versions of REFPROP are the work of ten co-authors and numerous other contributors, and Dr. McLinden has been a co-author of every release of the NIST REFPROP database from version 1 in December 1989 to the current version 10.0. REFPROP has its roots in an early, simple equation of state for refrigerant mixtures developed by Dr. Graham Morrison and coded by McLinden and informally distributed on magnetic tape. “REFPROP” originally stood for “REFrigerant PROPerties” and version 1 included just 15 pure refrigerants and their binary mixtures. Version 6 (1998) introduced a modern graphical user interface (coded largely by Prof. S.A. Klein of the University of Wisconsin) and a complete restructuring of the core property code (coded by McLinden). With version 7 the meaning of the name was changed to “REference Fluid PROPerties” to reflect the greater scope of the database. The current version includes 147 pure fluids and mixtures with up to 20 components. Natural gas constituents, other hydrocarbons up to hexadecane (C₁₆H₃₄), water/steam, cryogenic fluids, and other simple inorganic fluids are included in addition to refrigerants. Primary responsibility for REFPROP passed to Dr. Eric Lemmon in 2002 with version 7, but Dr. McLinden remains involved in its development and support.

• Morrison, G. and McLinden, M.O. (1986). Application of the Carnahan-Starling-DeSantis equation of state to mixtures of refrigerants. ASME Winter Annual Meeting, paper 86-WA/HT-59. https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=910738
• McLinden, M.O., Lemmon, E.W. and Huber, M.L. (2003). The REFPROP database for the thermophysical properties of refrigerants. 21st International Congress of Refrigeration, Washington, DC, International Institute of Refrigeration, paper ICR0443. https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=831869
• Lemmon, E. W.; Bell, I.; Huber, M. L.; McLinden, M. O. (2018). NIST Standard Reference Database 23, NIST Reference Fluid Thermodynamic and Transport Properties—REFPROP, version 10.0; Standard Reference Data Program, National Institute of Standards and Technology.
• Huber, M. L.;  Lemmon, E. W.;  Bell, I. H.; McLinden, M. O., (2022). The NIST REFPROP database for highly accurate properties of industrially important fluid. Ind. Eng. Chem. Res. 61, 15449-15472. https://doi.org/10.1021/acs.iecr.2c01427

Standard Reference Fluid p-r-T Data. Dr. McLinden’s measurements, and in particular those made with the two-sinker densimeter, feed into standards and improved fluid models and theory. His extensive measurements on propane were key data in developing a new equation of state that is among the most accurate for any fluid; propane is an important reference fluid for applications including natural gas and liquid fuels. In a collaboration with Dr. Michael Moldover of NIST, his measurements on helium were combined with theory to yield the most accurate virial coefficients available for this gas; these have been used in the development of a new primary pressure standard based on fundamental physical properties of helium. He demonstrated that high-accuracy density measurements on gases could determine thermodynamic temperatures and thus be the basis for a new type of gas thermometer. The densimeter was used to extend the range of the Standard Reference Material® for liquid density based on toluene from the near-ambient conditions of the previous SRM to –50 ˚C to 150 ˚C, with pressures to 30 MPa; this is the widest range of temperature and pressure for a density standard from any National Metrology Institute.

• McLinden, M. O. (2009). Thermodynamic properties of propane. I.  p-r-T behavior from 265 K to 500 K with pressures to 36 MPa. J. Chem. Engr. Data 54: 3181-3191. https://doi.org/10.1021/je900124n
• Lemmon, E. W., W. Wagner and M. O. McLinden (2009). Thermodynamic properties of propane.  III.  Equation of state. J. Chem. Engr. Data 54: 3141-3180. https://doi.org/10.1021/je900217v
• Moldover, M. R.; McLinden, M. O. (2010) Using Ab Initio “Data” to Accurately Determine the Fourth Density Virial Coefficient of Helium. J. Chem. Thermodyn. 42: 1193-1203. https://doi.org/10.1016/j.jct.2010.02.015
• McLinden, M.O. (2006) Densimetry for primary temperature metrology and a method for the in-situ determination of densimeter sinker volumes. Meas. Sci. Technol. 17: 2597-2612. https://doi.org/10.1088/0957-0233/17/10/011
• McLinden, M. O. and Splett, J.D. (2008). A liquid density standard over wide ranges of temperature and pressure based on toluene. J. Res. Natl. Inst. Stand. Technol. 113: 29-67. https://doi.org/10.6028/jres.113.005
  
   

Dew Points and Sorption Phenomena. The dew point, which is the boundary between single-phase vapor and the two-phase region, is important for many industrial processes, but unfortunately much of the dew point data in the literature has high uncertainties. In collaboration with Prof. Markus Richter of Chemnitz University of Technology (Germany), Dr. McLinden has begun a project to explore a new technique for measurining dew points of fluid mixtures. Also investigated are sorption effects near the dew point, such as capillary condensation (precondensation), in which the less-volatile component preferentially condenses, thereby distorting the composition of the mixture under study. Proof-of-concept measurements utilizing the NIST two-sinker densimeter were recently completed. He has worked with his collaborators to put into operation in Chemnitz a four-sinker densimeter optimized for the simultaneous measurement of density, dew points, and sorption effects. This work was part of a prestigeous Emmy Noether Group awarded to Prof. Richter by the DFG (German Research Foundation).

• McLinden, M. O.; Richter, M. (2016) Application of a two-sinker densimeter for phase-equilibrium measurements:  A new technique for the detection of dew points and measurements on the (methane + propane) System. J. Chem. Thermodyn. 99: 105-115.
• Richter, M. and M. O. McLinden (2017). Densimetry for the Quantification of Sorption Phenomena on Nonporous Media Near the Dew Point of Fluid Mixtures. Sci. Reports 7: 6185. https://doi.org/10.1038/s41598-017-06228-6
• Moritz, K.; Kleinrahm, R.; McLinden, M. O.; Richter, M., (2017). Development of a new densimeter for the combined investigation of dew-point densities and sorption phenomena of fluid mixtures. Meas. Sci. Tech.  28, 127007. https://doi.org/10.1088/1361-6501/aa940a
• Miller, S. L.;  Sartini, M.;  Windom, B.; Suiter, C. L.;  McLinden, M. O.;  Levinger, N. E.; Widegren, J. A., (2023). High-pressure vapor-liquid equilibrium measurements of methane + water mixtures by nuclear magnetic resonance spectroscopy. Gas Science and Engineering 120, 205165. https://doi.org/10.1016/j.jgsce.2023.205165

• Bernardini, L.;  Kleinrahm, R.;  Moritz, K.; McLinden, M. O.; Richter, M., (2024). The four-sinker densimeter:  A new instrument for the combined investigation of accurate densities and sorption phenomena of pure fluids and mixtures. Int. J. Thermophys. 45, 49. https://doi.org/10.1007/s10765-024-03336-0

   

Properties of Semiconductor Process Gases. The production of integrated circuits (“chips”) involves many gases as etchants, dopants, chemical vapor deposition agents, etc., and accurate metering of these gases into the process chamber is critical for maximizing device throughput and yield. Dr. McLinden is co-PI (with Dr. Jodie Pope of the Fluid Metrology Group of NIST-Gaithersburg) of a CHIPS-funded project “Gas Flow and Properties: Standards and Models for Flow Metering Semiconductor Gases” to address this need. The Fluid Metrology Group will be developing flow standards and models to extend the current state-of-the-art calibrations with nitrogen to any process gas. These require data for the properties of the gases, with density and viscosity being the most important. In addition to utilizing existing instruments in the group, Dr. McLinden and his colleagues in Boulder are developing three new instruments for these measurements: a dual-capillary viscometer for measurements at the lowest possible uncertainties on inert gases as well as a Greenspan viscometer and cylindrical acoustic resonator for measurements on a wide range of gases. A particular challenge is that many of these process gases are hazardous, and the latter two instruments are built of highly corrosion-resistant alloys and employ extensive safety protocols.

Professional Service

American Society of Heating Refrigerating and Air Conditioning Engineers (ASHRAE), Technical Activities Committee (1996–1999).

ASHRAE, Technical Committee 3.1–Refrigerants and Secondary Coolants (1986–present); Chair (1990–1992, 2000–2002, and 2014–2016).

ASHRAE, Standards Project Committee 34–Number Designation and Safety Classification of Refrigerants (1986–1989, 1990–1993, 2004–2010); Chair of Flammability Subcommittee (2007–2010).

ASHRAE, Standards Project Committee 177p—Method of Test for Measuring Fractionated Compositions of Refrigerant Blends (2005–2015).

ASHRAE CFC Position Statement Task Group (1992).

ASHRAE Refrigerants Position Statement ad hoc Committee (2010–2011).

ASHRAE Handbook Chapter Revisor, “Thermophysical Properties of Refrigerants” (1989, 1993, 1997, 2001, 2005, 2009, 2013, 2017, 2025).

International Energy Agency, Annex 18—Thermophysical Properties of the Environmentally Acceptable Refrigerants, Operating Agent [i.e., Chair] (1990–1999).

International Institute of Refrigeration conference “Thermophysical Properties and Transport Processes of Refrigerants,” June 23–26, 2009, Boulder, Colorado, Co-Chair.

ISO Working Group 17584 “Refrigerant Properties” (2000–2005, 2016–2020).

Symposium on Thermophysical Properties; Organizer of sessions on working fluids and refrigerants (1991, 1994, 1997, 2000, 2003, 2006, 2009, 2012, 2015, 2018, 2021, 2024).

United Nations Environment Programme; Montreal Protocol Assessment; Air Conditioning and Heat Pumps Technical Options Committee; Lead Author of “Refrigerant Data” chapter (1989, 1991, 1994).

World Meteorological Organization; Alternative Fluorocarbon Environmental Acceptability Study; Lead Author of “Physical Properties” chapter (1989).

Department of Commerce Silver Medal (1988), jointly with Graham Morrison, “For significant contributions to the U.S. refrigeration industry in the characterization and search for ozone-safe refrigerants.”

ASHRAE Journal Paper Award and the NIST Edward Uhler Condon Award (1988), jointly with David Didion, for authoring “CFCs—Quest for Alternatives.” The Condon award cited the paper as “a landmark contribution to the field of … refrigerants.” [M.O. McLinden and D.A. Didion. ASHRAE J. (1987), 29, (12), 32-42]

NIST Applied Research Award (1992), jointly with Graham Morrison, “For developing practical models for predicting the thermodynamic properties of refrigerants.”

NIST William P. Schlicter Award (1999), “For working closely with the air-conditioning/ refrigeration industries to replace ozone-depleting chlorofluorocarbons with environmentally acceptable alternatives.”

Department of Commerce/NIST Federal Engineer of the Year (1995).

NIST Judson C. French Award (2001), jointly with Eric Lemmon and Daniel Friend, “For the development of the NIST Pure Fluids Standard Reference Database that dramatically upgrades a key part of the nation’s metrology infrastructure.”

American Society of Heating Refrigerating and Air Conditioning Engineers (ASHRAE), Distinguished Service Award (2005) in recognition of those “giving freely of their time and talent to the Society.”

International Journal of Refrigeration Best Paper Award 2013/2014 for “A thermodynamic analysis of refrigerants: Possibilities and tradeoffs for Low-GWP refrigerants.” [M.O. McLinden, A.F. Kazakov, J.S. Brown, P.A. Domanski, (2014). Int. J. Refrigeration 38, 80-92.]

“Mercator Fellow” of the Deutsche Forschungsgemeinschaft (German Research Foundation)  (2015) for “intense and long-term collaboration” with the Emmy Noether Group “Dew-Point Densities of Fluid Mixtures—New Approaches for Measurement and Modeling” at Ruhr-University Bochum.

Rocky Mountain Eagle Award/Scientific Achievement of the Colorado Federal Executive Board (2017), jointly with Andrei Kazakov, for “providing industry with refrigerant options to transition to the next generation of refrigerants.”

Department of Commerce Gold Medal (2017), jointly with Andrei Kazakov and Piotr Domanski, “For identifying the best alternatives to hydrofluorocarbon chemicals essential to the future of the air-conditioning and refrigerating industries.”

Fellow, American Society of Heating Refrigerating and Air Conditioning Engineers (ASHRAE) (2018) in recognition of “Substantial contributions and distinction in HVAC&R and the built environment.”

J & E Hall Gold Medal of the Institute of Refrigeration (U.K., 2018) for “Innovation, application, and advancement of refrigeration.”

Donald L. Katz Award of GPA Midstream Association (2023) in “Recognition of outstanding accomplishments in gas processing research and technology.”

NIST Jacob Rabinow Applied Research Award (2023) (group award) for “Identifying non-flammable, low-global-warming-potential alternatives to the widely used refrigerant HFC-134a for U.S. military applications.”

Yeram S. Touloukian Award, American Society of Mechanical Engineers (2024) in recognition of  “outstanding technical contributions in the field of thermophysical properties.”