Remembering a few towering figures who reshaped modern refrigeration thinking.

Isaac Newton wrote in a letter to his fellow-scientist Robert Hooke, “If I have seen further it is by standing on the shoulders of Giants.” For the modern refrigeration community, one of the foremost of our giants, both physically and metaphorically, was Gustav Lorentzen, professor at the Norwegian University of Science and Technology in Trondheim.

The following notes are extracts from an appreciation of Professor Lorentzen that was written by my father, Dr. S. Forbes Pearson, when he was presented with the International Institute of Refrigeration’s highest award, the Gustav Lorentzen medal, in 2003.

He wrote: “My first awareness of Prof. Lorentzen was when I was a post-graduate student working on performance of refrigeration compressor valves at the Royal Technical College with Jim Brown. Prof. Lorentzen sent a student, Oivind F. Johansen, to work with us and to see what we were doing. My experience to that date had been on small open and hermetic compressors and I assumed that these modern compressors would be more efficient and effective than old fashioned ammonia compressors. I was surprised to learn from a clearly presented paper by Prof. Lorentzen that the long stroke, slow running ammonia compressor was much more efficient than the modern short stroke compressors designed for Freons.

“Prof. Lorentzen and I became interested in the possibilities of returning to the use of carbon dioxide at about the same time. He was interested in using carbon dioxide in supercritical cycles but I was interested in using it on an industrial scale in cascade systems and as a volatile secondary refrigerant. Some time before, I had patented an overfeed system that flooded the refrigerant evaporator and evaporated the excess refrigerant in a pressure vessel by heat exchange with warm liquid coming from the condenser. Gustav decided that a similar system could be applied to the transcritical cycle and arranged for me to be contacted to ask whether I would have any objection. I had no objections.

“The last time I met Professor Lorentzen was at Hannover, I think, at the last natural refrigerants conference that he attended shortly before his death. He was still the same Gustav, with a twinkle in his eye. He came up to me with Helge Lunde and said ‘Helge, this is Dr. Pearson. He has just written a remarkable paper on the applications of carbon dioxide.’ He left me unsure whether he meant that it was remarkably bad, or remarkably naïve, or for what it was remarkable. Helge, I am sure, was meant to think that Gustav approved of the paper. You could never be quite sure with Gustav.

“It is worth emphasizing the unique degree to which he combined academic and mathematical ability with practical engineering skills and understanding of real life processes. I shall not look upon his like again.”

The Hannover conference mentioned above was the first in a series of biannual meetings arranged by the International Institute of Refrigeration that, since 1996, have been named “The Gustav Lorentzen Conference.” GL2024, the 16th in this unbroken sequence, is being held at the University of Maryland, August 11 – 14, and will cover a wide range of topics related to the use of natural working fluids in refrigeration, air-conditioning and heat pump systems. ASHRAE has been a cosponsor of the GL conference for many years and expects to have a strong presence in Maryland this August.

Grateful thanks to my good friend Helge Lunde for reminding me of these recollections and sending me a copy.

A memorial to a refrigeration giant.

PHOTO COURTESY OF THE INTERNATIONAL INSTITUTE OF REFRIGERATION (IIR)