Refrigeration’s star engineer Forbes Pearson dies

UK: Stephen Forbes Pearson, co-founder of Star Refrigeration and one of the world’s greatest refrigeration engineers, has died at the age of 92.

Forbes was born in Pollokshields, Glasgow, and attended school at Paisley Grammar and then Kelvinside Academy. 

He considered becoming a doctor like his grandfather, Charles Stewart, but instead studied mechanical engineering at the University of Glasgow, graduating in 1953. 

He spent undergraduate summer vacations working in the Rolls Royce factory at Hillington and the Tecumseh compressor factory in Michigan, USA. The connection with Tecumseh Products was through his father, Stephen H Pearson, who was the works manager for L Sterne and Co. His father was also responsible for setting up the first hermetic compressor production line in Europe in 1948, which were made under licence from Tecumseh.

Following graduation Forbes enrolled at the Royal College of Science and Technology in Glasgow to complete a thesis on valve design for reciprocating compressors under the supervision of Dr Jimmy Brown, who remained a friend and colleague for life, working together on a wide range of technical developments in refrigeration. 

With his PhD complete, Forbes was appointed as scientific officer at the Torry Research Station in Aberdeen and spent three years developing techniques for freezing fish on trawlers to enhance quality and extend shelf life. This work included time spent in rough seas off the coast of Newfoundland.

Married in April 1959, Forbes returned to Glasgow, setting up home in Maryhill and joining his father at L Sterne and Co’s Crown Iron Works. As chief engineer for Sterne his work was divided between design of products, such as industrial compressors and heat exchangers, and design of industrial refrigeration systems. 

When the company decided to close down the industrial division in 1959 to focus on manufacturing domestic and commercial equipment,  Forbes and two of his colleagues, Bert Campbell and Anthony Brown set up Star Refrigeration Ltd in 1970, initially from the Pearson family home in Maryhill, moving a few months later to Thornliebank Industrial Estate on the south side of Glasgow.

Star Refrigeration quickly gained a reputation for innovative but robust and reliable engineering, mainly founded on the technical developments led by Forbes in his role as technical director. The range of his novel ideas matched the breadth of his scientific interests and included new system configurations such as the low pressure receiver, new control methods, new components including ball valves, tube ice makers, evaporative condensers, electronic logic controllers, high efficiency water chillers and novel freezing techniques. 

In the late 1980s the phaseout of CFCs under the Montreal Protocol prompted him to combine his knowledge of organic chemistry with his understanding of how compressors worked to create a range of refrigerant fluids suited to the rigours of extreme temperature operation. 

The intention was to provide Star with suitable fluids to replace the R12 and R502 that they had been using for industrial systems since 1970 but his new refrigerants were much more widely used in commercial refrigeration and so were licensed to major suppliers and were marketed all over the world. He was one of the first people in the world to recognise the possibilities of blending organic chemicals to create a refrigerant fluid mixture with particularly favourable properties for unusual or extreme operating conditions. 

This pioneering work led to the award by the International Institute of Refrigeration of their Gustav Lorentzen medal in 2003, only the second time that this international accolade was presented.

In parallel with the significant development of CFC replacements, Forbes also designed new systems for the traditional refrigerants ammonia and carbon dioxide. He was instrumental in the adoption of the latter as a viable refrigerant for commercial and industrial refrigeration applications around the world including the freeze-drying of coffee at -50°C, the freezing of pet food, the refrigeration of distribution warehouses and the cooling of mainframe computers. 

During his career with Star he was awarded over 100 patents for a variety of refrigeration innovations.

He was heavily involved with the Institute of Refrigeration, serving as president from 1987 to 1988, and helping to set up the Institute’s Scottish Branch in the mid 1970s. He was also a regular contributor of technical papers on a wide range of topics to the Institute of Refrigeration, receiving their Lightfoot medal for the best paper of the year on six occasions. Forbes also chaired the Institute’s technical committee for many years, was awarded the Institute’s Hall-Thermotank Gold medal in 1991 and the Institute’s Scottish Branch Kooltech medal in 1987. 

His service to the wider refrigeration community included many years on the British Standards Institute’s committee on refrigeration safety, latterly as chairman of both the BSI national committee and the European working group through the 1990s when he helped to introduce the first version of the European refrigeration safety standard, EN378. He was honoured to be appointed as a visiting professor in the Department of Mechanical and Aerospace Engineering at the University of Strathclyde, and he enjoyed mentoring undergraduate engineering students in their project work. He was also elected as an honorary life member of the International Institute of Ammonia Refrigeration in 2001.

Following a stroke in 2021, Forbes’ mobility gradually decreased to the point where, by the end of 2022, he was housebound. 

He is survived by his wife, Jean, daughters Muriel and Libby, and sons Stephen, Andy and Dave.