With a career spanning six decades, Sam Petrie’s experiences are as rich and varied as the landscapes he’s traversed.

©RACA Journal

©RACA Journal

Petrie matriculated at the Johannesburg Trades School, Smit Street, Braamfontein in 1958 and signed an apprenticeship with Penman and Jochelson as an electrical wireman. Like many HVAC engineers it was chance that took him in that direction. He worked for Hall Thermotank in their electrical department working on control panels.

A desperate call for help led Petrie to an offsite venue where malfunctioning 100kW ammonia air conditioning machines threatened to derail Christmas festivities. Armed just with his toolbox and resolve, Petrie dove headfirst into the fray. “Ammonia stink filled the air. But I knew I had to act fast. With a simple adjustment, I managed to save the day, earning the gratitude of the folks at the client company.”

Little did Petrie know, this fateful encounter would alter the course of his career forever. “I received an unexpected visit from the managing director. He handed me a ticket to the UK, offering me the opportunity to pursue a course in refrigeration.” He was invited to attend the UK City and Guilds’ ammonia refrigeration course.

Petrie subsequently immersed himself in a world of frozen foods at Table Top Foods in George, now known as McCain’s. “They had 5 000kW of ammonia refrigeration,” he explains. Duties included the physical maintenance of the equipment as well as upgrading of Skania Fluid beds and Lewis Tunnel IQF freezer equipment and plant. There followed many years of working, installing and maintaining large cold rooms and freezer rooms and equipment as well as large air-conditioning installations countrywide.

“Ammonia isn’t something to be trifled with,” he cautions. Recalling one particular mishap, Petrie says: “We lost just over 100 tons of refrigerant. It was chaos. But we dealt with it. That’s the thing about this job – you learn to adapt.”

In his varied career, from 1998 to 2015 he worked in the field of training of apprentices. As Petrie’s reputation grew, so too did his influence in the field. “I had become a consultant, a mentor, a trusted advisor,” he says. “From Melrose Arch to data centres, I left my mark on some of the most iconic projects in the industry.”

But perhaps Petrie’s greatest legacy lies in his dedication to nurturing the next generation of cold chain and HVAC professionals. “I’ve always believed in paying it forward,” he muses. “Whether it’s training apprentices or sharing knowledge with fellow enthusiasts, I’ve made it my mission to ensure that the flame of passion for refrigeration burns bright.

“I’ve always been drawn to the inner workings of refrigeration,” Petrie adds, his eyes alight with the spark of nostalgia. “From the snap action thermostats of yesteryear to the cutting-edge electronic controls of today, I’ve witnessed firsthand the remarkable evolution of the field.”

“Whether it was ensuring the seamless operation of a central plant or troubleshooting a malfunctioning compressor, I took pride in my work,” Petrie says. “At the end of the day, it was about ensuring that people could go about their lives without having to worry about the intricacies of refrigeration.”

One of the key innovations Petrie has followed is the implementation of hot-aisle/cold-aisle systems in data centres – a revolutionary approach to cooling that optimises energy usage while maintaining ideal temperatures for sensitive electronic equipment. By carefully managing airflow and strategically placing cooling units, data centre operators can achieve remarkable efficiency gains without compromising performance.

But as Petrie points out, the benefits of these technological advancements must be balanced with considerations of cost and environmental impact. In a world where energy consumption and greenhouse gas emissions are under increasing scrutiny, finding the right balance between comfort, efficiency and sustainability is paramount.

Moreover, Petrie highlights the importance of education and awareness when it comes to managing air conditioning systems effectively. From setting appropriate temperature thresholds to understanding the implications of energy usage, informed decision-making is crucial for both businesses and individuals alike.