ASHRAE Journal - July 2024 - 112

REFRIGERATION APPLICATIONS
COLUMN
Andy Pearson
The Giant's Shoulders
BY ANDY PEARSON, PH.D., C.ENG., FELLOW ASHRAE
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
A memorial to a refrigeration giant.
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
112 ASHRAE JOURNAL ashrae.org J U LY 2024
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.
Andy Pearson, Ph.D., C.Eng., is group managing director
at Star Refrigeration in Glasgow, UK.
PHOTO COURTESY OF THE INTERNATIONAL INSTITUTE OF
REFRIGERATION (IIR)
http://www.ashrae.org
ASHRAE Journal - July 2024

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