Reilly Professor of Mechanical Engineering
Purdue University
Dr. Eckhard A. Groll is the Reilly Professor of Mechanical Engineering and William E. and Florence E. Perry Head of Mechanical Engineering at Purdue University. He joined Purdue University as an Assistant Professor in 1994 and was promoted to Associate Professor in 2000, to Full Professor in 2005, and to the Reilly Professorship in 2013. He received his Diploma in Mechanical Engineering from the University of the Ruhr in Bochum, Germany, in 1989 and a Doctorate in Mechanical Engineering from the University of Hannover, Germany, in 1994.
Professor Groll teaches Thermodynamics and his research focuses on the fundamental thermal sciences as applied to advanced energy conversion systems, components, and their working fluids. Since joining Purdue, he has been the principal investigator (PI) or Co-PI on more than 120 research grants and more than 40 educational grants with a total budget of approximately $13.6 million from various agencies, including ARPA-E, the California Energy Commission (CEC), the Department of Energy (DOE), the National Science Foundation (NSF), the U.S. Army and U.S. Air Force, and more than 30 different industrial sponsors. He has advised more than a 100 graduate students and more than 150 undergraduate project students, visiting scholars, and visiting research associates. He has authored or co-authored more than 370 archival journal articles and conference papers. He has been the co-author of 4 book chapters and the editor or co-editor of 7 conference proceedings. He holds 4 patents. He has a given 88 invited lectures and seminars, and 13 conference keynote lectures. He serves as the Regional Editor for the Americas for the International Journal of Refrigeration and he has organized and chaired 11 international conferences on topics of Refrigeration, Air Conditioning, Compressors, and Natural Working Fluids.
Dr. Groll has been recognized for his academic leadership in higher education. He is a 2010-2011 Fellow of the American Council on Education (ACE) and 2009-2010 Fellow of the Academic Leadership Program of the Committee on Institutional Collaboration (CIC-ALP). He has received numerous awards for his research and teaching excellence including most notably the 2018 J&E Hall International Gold Medal in Refrigeration by the Institute of Refrigeration and the 2017 Peter Ritter von Rittinger International Heat Pump Award by the IEA Heat Pump Centre. In addition, he was inducted into Purdue’s Book of Great Teachers in 2008.
In recent decades, the refrigeration and air conditioning sciences have been in a state of flux primarily because of the phase-out of ozone-depleting CFC and HCFC refrigerants, and secondarily because of environmental concerns related to the direct global warming impacts of some of the replacement refrigerants. Due to these concerns, there is significant worldwide interest in using substances that are naturally occurring in the biosphere as refrigerants, which are considered benign to the environment and are termed “natural working fluids”. Surprisingly, many of these substances were already used as refrigerants at the dawn of the refrigeration technology in the late 1800’s. Thus, when looking at the refrigerants of the future, it is essential to understand which substances have been used in past. This presentation provides a detailed review of the past and present refrigerants, and proposes refrigerants and their respective technologies that could be used in the future. An assessment of their characteristics related to choice of one versus another, and an identification of trends set by these choices will be made.
The phase-out of CFC and HCFC refrigerants, combined with advances in compressor technology such as reduced noise and vibration and mechanical capacity control, has motivated the development of novel compression concepts for the refrigeration industry. This paper provides an overview of several new developments for refrigeration, air-conditioning and heat pumping applications, including two novel compressors called the bowtie compressor and z-compressor. The bowtie compressor offers an integrated method of capacity modulation for use in domestic refrigerators/freezers. It modulates the cooling capacity by changing the piston stroke without changes of the clearance volume for better thermodynamic efficiency. The compressor is called bowtie compressor due to its two sector-shaped, opposing compression chambers forming a bowtie. The z-compressor is a dual-chamber hermetic rotary compressor with opposing upper and lower compression chambers separated by z-shaped blade. The compressor offers significantly lower noise and vibration levels than a conventional rolling piston compressor. In addition to presenting these new compressor types, research on flooded compression, miniature-scale compression, and compression processes with multi-port refrigerant injection will also be presented.