Like most characters of notoriety, R22 has many aliases, including chlorodifluoromethane (CHClF2), hydrochlorofluorocarbon-22 (HCFC-22) and difluoromonochloromethane. Call it what you like - our dependence on this and other HCFCs is coming to an end.
Although R22 has long been recognized as an effective way to move waste heat in chillers, the scientific community has identified this refrigerant as an ozone-depleting compound. As a result, effective January 1, 2010, no new equipment charged with R22 can be manufactured in the United States, and the production of this refrigerant will be phased out over the next decade.
The TimelineDespite R22’s sinister reputation, it is actually far less harmful to the environment than its predecessors. The environmental impact of a gas is measured by its ozone-depletion potential (ODP), which is the relative amount the element contributes to ozone layer degradation, and global warming potential (GWP), which is the relative amount the element contributes to global warming compared to the same mass of carbon dioxide, which has a GWP of 1. Trichlorofluoromethane (R11) and dichlorodifluoromethane (R12), which were common refrigerants until they were banned under the Montreal Protocol in 1994, have a 100-year GWP of 4,600 (4,600 times the carbon dioxide standard) and 8,100, respectively, and an ODP of 1.0. R22 has a much lower 100-year GWP of 1,700 and an ODP of 0.5.
But these figures aren’t low enough. Under a 1992 amendment to the Montreal Protocol, which is implemented in the United States by the Environmental Protection Agency through Title VI of the Clean Air Act, HCFCs, including R22, must be phased out in favor of ozone-friendly refrigerants.
What does this mean for your plant? If your chiller uses R22 - and most of the chillers in operation right now do - you can legally continue this use until January 1, 2030. However, as restrictions on producing and selling this refrigerant increase over time, R22 will become more expensive and more difficult to obtain. By January 1, 2020, the production and import of R22 will be banned in the United States, and only recycled quantities of the refrigerant will be available. It is wise to begin planning now.
The AlternativesChillers that rely on environmentally acceptable hydrofluorocarbon (HFC) refrigerants such as R407c or R134a are readily available. Additionally, most chiller manufacturers have developed retrofit solutions for existing R22 chillers, so you do not necessarily have to replace all of your chillers with new models.
Unfortunately, making the switch is not as simple as it sounds. In the short term, there may be some localized shortages of alternative refrigerants. What is more, HCFCs such as R22 are good at moving heat, and CFCs were even better. Modern ozone-friendly replacements can actually be as much as 40 percent less efficient in comparison. For example, a chiller used to cool a 10-kW laser using R22 might only be capable of cooling a 6-kW laser using an HFC. Good for the planet, yes, but not great for your process. Table 1 compares the performance of a chiller using R22 and R407c.
Additionally, while some conversions will involve simple refrigerant swaps, others will require different compressors, control valves or other components. And, when considering the purchase of a replacement chiller, it will be critical to understand your heat load.
If you are still using R22, you should contact your equipment supplier to begin developing a phase-out plan. Many variables must be considered when making the change. Partnering with a knowledgeable chiller manufacturer can go a long way toward facilitating the transition.