Obituary: Pega Hrnjak

The IIR is deeply saddened to learn that Professor Predrag (Pega) Hrnjak passed away on August 31, 2022, at the age of 70.

Born in Belgrade, Yugoslavia (now Serbia), Pega Hrnjak received a PhD from the University of Belgrade, where he taught for many years. He emigrated to the U.S. in 1993, becoming a Stoecker Faculty Fellow and Distinguished Research Professor at the University of Illinois at Urbana-Champaign, as well as co-director and then director of the University’s Air Conditioning and Refrigeration Center (ACRC). He founded Creative Thermal Solutions (CTS), a research and consulting firm, in 2003.

The University of Illinois reports that he has guided nearly 120 students to graduate degrees, with more than 30 completing a doctorate, adding “His students have gone on to leadership positions in industry, national labs and public service, and to careers in the academy—all around the world.”

Pega Hrnjak has been recognised internationally for his technical leadership, receiving the Ritter von Rittinger award (2008), the IIR Gustav Lorentzen Medal (2011), the J&E Hall Medal (2012), and the ASHRAE Holladay Distinguished Fellow Award (2019).

He has been very active in the IIR, particularly in the US Committee. He was a member of IIR Commission E2 on heat pumps and energy recovery.

Pega Hrnjak has participated or contributed to the organisation of many IIR conferences. He has also written numerous articles for the International Journal of Refrigeration. Thus, more than 300 papers or articles he authored or co-authored are available in the IIR FRIDOC database.

The IIR extends its sincere sympathy to his family and relatives.


Information provided by Stefan Elbel, Research Assistant Professor at the University of Illinois at Urbana-Champaign, member of IIR Commission D2. Picture procided by University of Illinois Urbana-Champaign (link).