CCN takes a fascinating look at the industry's evolution over the past 30 years including system failures, mismatched refrigerant blends and rotten pineapples - the RAC trade has seen it all.
In this article, industry veteran and international standards expert Kevin Lee, shares entertaining insights into how the industry was forced to change when the Montreal Protocol was introduced in 1987. He writes:
The CFC phase-out played a pivotal role in the development of refrigeration and air conditioning technologies. This article looks at some of the biggest changes and the biggest challenges the industry has faced during this time.
The CFC phase-out led to significant advances – some were technical while others led to changes in practice - creating a better industry one that is more professional and has better engineered equipment. While the end result was favourable don't think for a minute that the transition was easy or painless, it wasn't.
The changes in work practices were extensive and touched on many aspects of what a tradesperson was asked to do. CFCs were seen as valuable but also as something that could not be vented off without harm. CFCs could no longer be used instead of compressed air to blow the dust and lint out of condenser coils and the need to recover CFC refrigerant from systems during service and decommissioning was a necessary improvement. These practices led to a far more professional and environmentally responsible industry.
Other changes were no less profound - the new refrigerants presented real problems for industry as they could not be simply used as drop-ins to replace CFCs. CFC refrigerants used mineral oils in the compressors, which were miscible (mixed readily) with the refrigerant so it could travel around the system and return to the compressor. Mineral oil was not miscible with HFC refrigerants and this presented problems in that all compressors pump a small amount of oil out with the refrigerant and around the system.
As the oil was not miscible it did not remain mixed with the refrigerant and tended to accumulate in various sections of the refrigeration circuit. The choice of lubricant to use with HFCs came down to either Polyol Ester (POE) or Polyalkylene Glycol (PAG). Both of these lubricants presented their own problems with the main one being they both readily absorbed water.
The presence of water in a refrigeration system is a major reliability threat as the water can break down to form very damaging acids and result in the ultimate failure of the system. Vastly improved work practices were needed as systems could not be left open to the atmosphere as the oil would absorb moisture.
Additionally, there was recognition that refrigerant leaks were a major problem and that regular refrigerant top ups were inappropriate. This issue stemmed from the original design and manufacture of the system components - such as condensing units and evaporators - and from field installation practices. It was common practice to use mechanical joints rather than soldered joints to attach such items as shut-off valves, regulators, filter dryers and TX valves.
This of course made servicing easy but created many sources of potential leaks. Both better field practice and improved design helped address this problem.
The phaseout of CFCs did present other issues to industry – over time there was an absolute plethora of blends available, over 50 at one point. It was basically left to the marketplace to determine which ones worked best for a particular application. Also, in the early days, some of the mixing of the blends themselves was not consistent and this led to low system performance and even failures.
There were horror stories of systems failing catastrophically and when the compressors were opened up they had a bright green jelly-like substance that smelled of rotten pineapples. Some of the refrigerant blends used ethanol to help carry the oil around the system, if the system had moisture in it and acids formed then the ethanol could react with the acids to form esters and hence the rotten pineapple smell.
The number and range of refrigerants led to another problem - refrigerant cylinders became a nightmare for tradesmen. They had their workshops and work trucks full of different cylinders - some they owned, others they rented, and others were owned by the refrigerant wholesalers. To add to this challenge, they also needed to carry reclaim cylinders.
To get the cylinder nightmare under control the major wholesalers and refrigerant distributors put in place cylinder-tracking systems, decanting at wholesale branches was discontinued in favour of centralized cylinder filling plants that also checked cylinder pressure test date, cleanliness and leak tightness of the filling valve.
Once these centralized systems were well established thousands of potentially leaking cylinders were removed from the market. I firmly believe that this change and the advent of reclaim cylinders led to a vast improvement in the overall quality of refrigerant and reduced a huge source of leaks.
Both equipment and work practices today are amazingly advanced from what they were 30 years ago. Our industry isn't just moe advanced, equipment is better designed, and we have better trained tradespeople using better practices than we did in the 1980s and before.
While we certainly can all identify with the upgrades the industry should pursue, we shouldn't forget the catalyst that made it all happen – the Montreal Protocol. Today's industry is successfully managing the environmental impacts of refrigerants and reducing the energy use of our equipment.
From this starting point it will be interesting to see what the next evolution of the trade looks like in the year 2050.