Malcolm Edwards, technical manager at ICS Cool Energy.
In light of F-Gas legislation requiring a reduction in the use of HFC refrigerants and a move towards the use of refrigerants with lower global warming potential (GWP), selecting a suitable refrigerant has become an extremely complex task. The industry’s refrigerant options have been limited significantly, particularly when other factors, such as volatility and operational efficiency, are considered.
Malcolm Edwards, technical manager at ICS Cool Energy, explained: “There is no off-the-shelf solution when it comes to refrigerants, particularly for low temperature applications, and companies face a careful balancing act between GWP, toxicity and flammability. For example, A2Ls, which meet the F-Gas legislation criteria of low GWP, are classed as mildly flammable, which obviously poses safety risks when it comes to their transportation and handling.
“Therefore, systems need to be designed in line with refrigerant development, preferably without the need for special transport and storage arrangements or imposing severe commercial pressures. With more flammable refrigerants coming to the fore, the importance of safer logistics, better fire-proofing, and keeping systems secure to prevent leakage is paramount. Refrigerants should be contained, recovered, and disposed of ethically.”
Mr Edwards continued: “What’s more, natural refrigerants such as carbon dioxide (CO2) and ammonia (NH3), which have low GWP, won’t suit every application either. For example, ammonia provides high efficiency and performance with low environmental impact. However, it has high toxicity, can be flammable, and is highly corrosive to copper which is an issue for many semi-hermetic compressors, which often rely on having electric motors with copper windings.
“Another issue is the encouraged use of drop-in refrigerants which don’t have GWP values under 150. Drop-in refrigerants are never 100 percent like-for-like and will therefore compromise performance or energy consumption. Systems often need altering before a drop-in refrigerant can be used, including changes to the expansion valve, additional liquid suction heat exchangers, or changing the oil to a different type.”
Mr Edwards concluded: “There is no straightforward answer when it comes to refrigerant choice, and with the market saturated with conflicting information, end users need to be aware of the compromises associated with hastily opting for low GWP and drop-in refrigerants. Only when refrigerant producers and system manufacturers work together can end users have peace of mind that their systems will operate efficiently, safely and in an environmentally friendly manner.”