The US-based chemical engineer led a team to identify the best candidates for the next generation of low global warming potential (GWP) refrigerants. The award was presented at the Institute of Refrigeration annual dinner in London on 21 February.

Dr McLinden was the principal investigator for the ground-breaking five-year project funded by the US Department of Energy. His team applied its combined expertise in chemistry, thermodynamics and refrigeration to the research, which has greatly helped the heating, ventilation, air conditioning, refrigeration and chemical industries to comply with international regulations. 

Dr McLinden, who is based at the National Institute of Standards and Technology (NIST) in Boulder, Colorado, said: “I am very honoured and somewhat surprised to receive this award. When you look at the list of past recipients of the J&E Hall Gold Medal you see folks who are absolute leaders in the refrigeration field – so it is an honour to join that group. I know a few of the past recipients personally. I am surprised perhaps because the award usually seems to go to people who invent a new technology or perhaps implement a technology in some new way. 

“My work is much more fundamental thermodynamics, so it is a little bit out of the mainstream of refrigeration technology. It is very nice to see the fundamental thermodynamics that I work in being recognised. I certainly could not have done it without the team. I have been very fortunate to have been working with some very good people on this project and many other projects over the years.”

Using machine and computer-led artificial intelligence, Dr McLinden’s team identified the fundamental thermodynamic characteristics of the ideal refrigerant. They then carried out a systematic and exhaustive screening of a comprehensive database of 60 million molecules to identify those with the right characteristics. Eventually, a set of 27 best candidates was identified. 

No fluid was found to be ideal in all respects and the study recommended refrigerant blends as a way to find a compromise between competing environmental, safety and performance requirements. Work to identify the best blends is continuing.

Dr McLinden has been actively engaged in researching new refrigerants for virtually his entire career. He was one of the original developers – with Graham Morrison – of the NIST REFPROP database which has become the standard for refrigerant properties in the industry and which is widely used in the design of refrigeration equipment.

He was heavily involved in the phase out of the ozone-depleting CFC and HCFC refrigerants in the 1990s, and the setting of standards for the thermodynamic properties of the then-new HFCs.