14 / 14 / 2017 by IDW

For years, synthetic refrigerants have been a mainstay in the commercial refrigeration industry.  In this article, we’ll discuss what man-made refrigerants are, why they have been so popular for commercial refrigeration applications, and what the pros and cons of using them are.  In doing so, we’ll also look at how natural refrigerants have seen a resurgence in use in modern refrigeration applications, and why many manufacturers are turning to natural refrigerants over man-made refrigerants for their newest product lines.

        The most popular synthetic refrigerants used in the modern world are chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), and hydrochlorofluorocarbons (HCFCs).  When synthetic refrigerants first began to be utilized, they operated more efficiently than other natural refrigerants due to technological limitations at the time.  One other advantage that synthetic refrigerants had over their natural counterparts was inherent stability.  Synthetic refrigerants are non-flammable, making them safer in legacy systems where fire was a concern.

 

        Unfortunately, synthetic refrigerants had a couple of significant downsides which are still being dealt with around the world.  Use of CFCs and HCFCs has been heavily regulated since the introduction of the Montreal Protocol.  The Montreal Protocol sought to curb the growing damage to the ozone layer that was being documented during the late 1970’s and 1980’s.  Enacted in 1989, the Montreal Protocol specifically targeted refrigerants that had a high ozone depletion potential (ODP), which included both CFCs and HCFCs.  As an alternative, commercial refrigeration manufacturers turned to HFCs, which have no impact on the ozone layer, while still maintaining the inherently low flammability levels of synthetic refrigerants. HFCs are still in use till this day, although their use is now being phased out as they have a high global warming potential (GWP) and have been shown to contribute to global warming.

 

        The phase-out of HFCs over the next couple of decades has pushed commercial refrigeration manufacturers to seek out new refrigerants that have a low ODP, low GWP, and yet allow for increased efficiency within their units.  One synthetic alternative to HFC’s that is being explored is hydrofluoro olefins (HFOs).  Unlike the other popular synthetic refrigerants, HFOs have a very low GWP and ODP, making their contribution to global warming and ozone depletion much lower.  However, the use of HFOs in the commercial refrigeration industry is controversial.  Proponents of HFOs argue that they represent a synthetic refrigerant that is safer than some natural alternatives, due to their non-flammable nature, while also being more environmentally friendly than other synthetic alternatives.  Those opposed to HFOs argue that they produce a toxic byproduct in the atmosphere called trifluoroacetic acid (TFA), which may have a detrimental impact particularly in watersheds and aquatic environments.  Additionally, the production of HFOs requires synthesis of HCFCs, so in order for HFOs to be produced on a large scale it would require manufacturers to continually produce HCFCs as well.  Because TFAs appear in the environment from both natural and man-made sources, the concern is that widespread use of HFOs could result in dangerously high concentrations over time.

 

        The negative impact of synthetic refrigerants, in conjunction with regulatory changes that increasingly limit their use, has enabled to commercial refrigeration manufacturers to seek out alternative natural substances.  The most common natural refrigerants include hydrocarbons (HCs), Isobutane, Propane, Ammonia, and C02.  Although some of these refrigerants were used as far back as the late 19th and early 20th century, their use became eclipsed with the rising popularity of synthetic refrigerants.  During their early use, natural refrigerants were too unstable to see widespread application, as their flammable nature and technological constraints in design and manufacturing resulted in sometimes dangerous applications.  However, commercial refrigeration manufacturers are returning to these substances as a solution to climate change and demands for increasingly efficient refrigeration units.  Modern commercial refrigerator design has enabled manufacturers to use natural refrigerants such as HCs in closed systems which are just as safe as systems that use synthetic refrigerants.  Commercial refrigeration units that use natural refrigerants are able to operate more efficiently, which reduces energy costs for the end-user and reduces the workload on the unit itself.  Natural refrigerants such as HCs are also much more environmentally friendly than synthetic alternatives, which has allowed commercial refrigeration manufacturers to design coolers that are future proofed against further regulatory changes.