Although ozone-depleting refrigerants have been virtually phased out for a number of years, today’s concerns focus on the global-warming potential (GWP) of refrigerants.
GWP is an estimate of how much a given mass of a gas will contribute to global warming – also called the greenhouse gas effect. Traditional synthetic refrigerants, when released into the atmosphere, can act as heat-trapping greenhouse gases because of their molecular complexity.
With its GWP of one, CO2 is, essentially, the baseline against which all other refrigerants are measured. Although there are hundreds of man-made refrigerants, CO2 is part of a small family of “natural refrigerants,” or refrigerants that occur in nature. CO2 refrigerant, also known as R-744, compares favorably against current contemporary hydrofluorocarbon (HFC) container refrigerants R-134a and R-404A, which have GWPs of 1320 and 3260, respectively.
Although other synthetic refrigerants are under development with lower GWPs than current HFCs, none approach CO2.
Moreover, with CO2 refrigerant shipping lines don’t have the concerns with flammability or high toxicity that they might have with other refrigerants, even some natural refrigerants, such as butane and ammonia.
One challenge CO2 presents to container refrigeration is the need to use it at high operating pressures in an energy-efficient manner. NaturaLINE™ technology has been developed to address these obstacles. The amount of refrigerant required by systems using NaturaLINE technology is about the same as Carrier’s current product offerings. And the energy requirements are targeted to achieve best-in-class performance, all of which makes NaturaLINE technology the natural choice for the next generation of container refrigeration.
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