Goddard Space Flight Center, Greenbelt, Maryland 20771
ENGINEERING COLLOQUIUM
Monday, October 25, 2010 / 3:30 PM, Building 3 Auditorium
Steven Brown
"Refrigerants and Global Climate Change"
ABSTRACT -- Global climate change is leading many constituencies, particularly governmental agencies and governments, to push the refrigeration industry to replace halocarbon refrigerants possessing large Global Warming Potentials (GWPs) with ones, e.g., natural refrigerants, possessing much lower GWPs. Examples of legislative efforts include, among others, Europe's F-Gas regulations and HFC taxes imposed by some Scandinavian countries. The seminar will present a brief historical summary of the recent past and current status of refrigerants, particularly focusing on recent research and development activity that has been initiated and is ongoing to investigate fluorinated propene (propylene) isomers as potential refrigerants possessing low GWPs. The catalyst for much of this effort can be attributed to European regulations regarding the use of R-134a in automotive applications, which specify beginning on January 1, 2011 new models and on January 1, 2017 new vehicles fitted with air-conditioning cannot be manufactured with fluorinated greenhouse gases having GWPs greater than 150. Among possible candidates that meet this criterion are R-152a, CO2, and the fluorinated propene isomer R-1234yf (GWP = 4). The remainder of the seminar will discuss, in addition to R-1234yf, several other fluorinated propene isomers, all of which have limited thermodynamic property data published in the public domain. In particular, their refrigerant numbering scheme will first be summarized. Second, the flammability and toxicity of these isomers will be briefly addressed. Third, estimated fundamental parameters and thermodynamic properties for eight of these isomers will be presented. Finally, the ideal cycle performances of these eight isomers will be estimated for three typical applications.
SPEAKER -- J. Steven Brown received his Bachelor of Mechanical Engineering from Georgia Tech in 1987 and his Ph.D. in Mechanical Engineering from M.I.T. in 1991. He joined the Climate Control Division of the Ford Motor Company in 1992 as a Product Design Engineer where he designed air conditioning and heating systems. While at Ford, he was an Adjunct Lecturer at The University of Michigan-Dearborn where he taught graduate level courses in thermodynamics.
He joined the Mechanical Engineering Department of The Catholic University of America as an Assistant Professor in January 1998, and was promoted to Associate Professor in September 2002. He served as Chair of Mechanical Engineering from June 2001 through August 2008.
His research interests lie in the areas of air conditioning and refrigeration, alternative refrigerants and cycles, Organic Rankine Cycles, thermodynamics, and two phase flow and heat transfer. In addition to his responsibilities at The Catholic University of America, he has been a Guest Researcher at The National Institute of Standards and Technology, has worked two summers at NASA-Goddard, and spent the 2008-2009 academic year on sabbatical at the University of Padua, Italy.
He is the recipient of the Outstanding Faculty Teaching Achievement Award from the School of Engineering of The Catholic University of America in 1999, the Ralph Teetor Educational Award from the Society of Automotive Engineers in 2001, the DuPont Young Professor Award in 2001, the Kaman Excellence in Teaching Award from the School of Engineering of The Catholic University of America in 2004, and is the recipient of the Best Paper Award for 2009 from ASHRAE Journal.
He has served as an ABET Mechanical Engineering Program Evaluator since 2006, and is a member of IIR, ASHRAE, ASME, and is a registered professional engineer in the State of Maryland.