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© Cold Link Africa | Benjamin Brits
Taking a closer look at all the elements involved , one realises the vastness of the cold chain . The taxonomy here would possibly run into many thousands of items . From the simplest sensors to the most extravagant plants the world has seen , or the technology involved in ‘ plug ‘ n play ’ equipment to the doors , seals and insulation of display cabinets or freezers . The advancement on all fronts to achieve better control , accuracy and ultimately efficiency is ongoing . Of late , world bodies and authorities have become increasingly vocal around two particular factors that persist to come to the fore – which also relate directly to the cold chain : energy consumption and food waste . Now , as the ‘ custodian ’ in the preservation of perishable products the cold chain will continue to remain essential in food supply chains ( and food safety ), and further as one of the largest users of energy , continual innovation is again essential as globally the struggle to manage and forecast energy demand becomes a greater and greater task .
“ The improvement of refrigeration technologies overall has made it possible to extend the shelf life of food , which has a relevant impact on reducing food waste and increasing food safety . The type and mix of equipment used in a refrigeration system plays a definite role in the stability of temperature and humidity where food is
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An ammonia refrigeration system installation . |
© Cold Link Africa | Benjamin Brits |
A CO 2 installation showing the gas coolers .
stored in a cold store or supermarket outlet , and thus affects the impact in the objective of preservation ”, says Carel Industries .
The whole point of maintaining the cold chain is to avoid the deterioration of the properties of any perishable product to the point of affecting its marketability or ‘ value ’. This factor depends on the combined action of specific enzymes typical of tissue cells and the microbes that contaminate food .
The overall effect is the formation of organic substances with a low molecular weight ( containing nitrogen and sulphur ) that
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modify the smell , taste , and colour , when considering foodstuff as an example , in a negative or unpleasant way . That hydrolytic action also breaks the product ’ s structure , frequently causing irreversible modification to some rheological properties ( softening of the food , for example ).
The cold chain remains the best way to limit or slow down microbial multiplication and thus produce a reasonable preservation period for food perishables . This period can vary , even considerably , depending on the type of food , its physical state , its history before being placed on the market ( good hygiene practices during processing immediately prior to being placed on the market ), the time of year , the specific batch of product , botanical variety , and so on .
Among the different steps in the cold chain , the choice of reliable technologies cannot be more emphasised . Produce may constantly be exposed to factors such as temperature variability due to the influx of ambient air , proximity to lights , defrost cycles , air flow , and differences in set point temperature from the producer to a retail cabinet . In South Africa , there is a general perception of clients wanting only the ‘ cheapest solution for now ’, without any forethought to the future and how these decisions will impact their businesses down the line .
“ In recent years , most of these variables have been improved notably thanks to more accurate design and improvements in technologies which include DC inverter
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technologies , that together with the use of electronic expansion valves and more advanced control and supervisory systems , have led not only to system energy savings but also greater stability of the parameters in various refrigeration systems from complete plants to stand-alone cabinets ”, Carel Industries states further .
THE CHANGING LANDSCAPE OF REFRIGERATION SYSTEMS Another major factor in the equation here that does not necessarily affect all components , but is a major one , is the phasing out of older global warming potential and ozone depleting refrigerants ( Chlorofluorocarbons or CFC and Hydrochlorofluorocarbons or HFCFC ) that has resulted in a worldwide drive towards natural refrigerants . Ultimately narrowing down the list - three ‘ main contenders ’ remain : ammonia ( R717 ), carbon dioxide CO₂ ( R744 ) and propane ( R290 ). Each of these have their own best suited application , pros and cons ( or risks to be more technically correct ).
A lot of reports now exist where you would read statements such as ‘ what will win the race – ammonia or CO₂ as the dominant global refrigerant ’ or reports highlighting the risks over rewards of each . Speaking to several industry players , the debate may go on for a very long time into the future as engineers and companies alike will have their natural preference , but many are also confident that systems of the future will incorporate more than one refrigerant ( operating as required per temperature range of course ).
“ Historically , refrigeration systems always took a standardised approach when it came to their design and construction . Over time , cooling trended toward no longer being engineered as much as a replication-model exercise using decades-old , but proven designs . This was the case for any new facilities . Ultimately , the result was that specifically industrial cooling systems started falling behind when it came to inclusion of the latest available technology . Times have however quickly changed due to several factors . Facilities around the world are facing higher average ambient temperatures while at the same time need to reduce energyuse and minimise climate-impact . Innovative technologies and improved refrigeration systems that employ natural refrigerants have quickly gained traction .
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