The choice of refrigerant to be used in various applications is a critical decision that has a myriad of impacts, from cost considerations to environmental effects. Among all such effects, the global warming potential (GWP) is perhaps the most important. Low-GWP refrigerants are better in terms of their contribution to climate change; as such, when deciding which refrigerant to use, it is imperative to consider which option has the lowest GWP. Despite the fact that many refrigerants exist, the three primary contenders in the international market are hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs) and hydrocarbons (HCs).
Among the three, hydrocarbons have the lowest GWP, making them the ideal refrigerant for those looking to reduce their impact on the climate. Hydrocarbons are naturally occurring, non-toxic and non-flammable gases that have the highest thermodynamic efficiency and lowest GWP of any available refrigerant (less than 1/10,000th that of carbon dioxide). Additionally, given that hydrocarbons are being used on a larger scale than ever before, the potential for a longer shelf-life of refrigeration hardware is inevitable, since the impact on the ozone layer is non-existent.
It is important to note, however, that while hydrocarbons are optimal in terms of their low GWP, they may not be suitable in certain applications. Furthermore, despite their vaunted GWP, hydrocarbons pose a variety of other risks, including the challenge of storing and handling the refrigerant safely. This often necessitates specialist containment and ventilation systems in order to comply with local regulations. Consequently, while hydrocarbons offer certain advantages in terms of their low GWP and ozone safety, they can often be difficult to implement in practice.
HCFCs, such as R22, are the most popular refrigerant in the global market, due to their widespread availability and relatively low cost. However, their popularity must be weighed against their relatively high GWP, which is approximately 10,000 times higher than that of carbon dioxide. Moreover, their high GWP means that HCFCs are now being phased out, in line with the Kigali Amendment of the Montreal Protocol. As such, HCFCs should be replaced when feasible, so as to ensure compliance and reduce carbon footprint.
Finally, HFCs have an intermediate GWP, ranging from 700 to 3,200, depending on the specific chemical compound. Furthermore, their ability to contribute to the depletion of ozone is lower than both hydrocarbons and HCFCs, but still significant. Given the environmental impacts of HFCs, they are now being phased out as well, and must be replaced with a low-GWP alternative like hydrocarbons.
In conclusion, hydrocarbons offer an optimal option in terms of GWP, as they do not contribute to ozone depletion. While they may not be suitable in certain applications, they can offer important environmental benefits when possible. HCFCs and HFCs are inferior to hydrocarbons in terms of GWP, and are often are now being phased out. As such, when deciding which refrigerant to use, those wishing to reduce their environmental impact should opt for hydrocarbons whenever possible.
