It has been a year since the Environmental Protection Agency instituted a number of changes to 40 CFR Part 82, Protection of Stratospheric Ozone. These changes are meant to sharply restrict the use of substances that allegedly harm the earth’s protective ozone layer and contribute to climate change. The targeted chemicals are HCFCs primarily used as refrigerants, specifically R-22, -142b, -123, -124, -225ca, and -225cb. These chemicals, if leaked into the atmosphere, deplete the stratospheric ozone layer and are being phased out under the Montreal Protocol. According to scientists, by cutting the production and import of these chemicals and limiting how they can be used, the rules will help the ozone layer heal faster.
As of Jan. 1, 2010, R-22 — what had been the primary refrigerant used in aircraft ground support preconditioned air units, home air conditioners for the building trades, industrial and commercial air conditioners, and other applications — could not be incorporated in equipment for new installations. This was not a surprise; indeed, Europe had banned HCFCs in 2005. In the United States, manufacturers of industrial and commercial air conditioners and the construction industry were ready for the change. They had decided on a new “standard” refrigerant, designed the equipment, and had an inventory of units ready to meet the requirements of new projects as they came along. PCA acquisition documents, however, were still listing R-22 as recently as December 2010, and some PCA manufacturers were struggling with the reality that design work was a necessity and that components for the “legal” refrigerants cost more than those for R-22.
The U.S. ground support industry stood and watched as 2009 passed and 2010 rolled in with new rules for preconditioned air equipment. Neither the airlines, nor the airport authorities, nor the PCA suppliers had come to any consensus as to what direction to take for an application that required economical, effective cooling. Unitron conducted a survey of airlines and airports in 2009. This survey asked which refrigerant their organization had selected to meet the requirements of the new environmental law, or if they had made a selection. Most respondents had made no selection, and some did not realize that a “deadline” loomed. Part of the reason for this was past experience with projected EPA mandates, some that were delayed time and time again. The final guidelines for phasing out R-22 (and similar refrigerants) were not passed until Dec. 28, 2009, but they were passed and the start date remained Jan. 1, 2010. Manufacturers’ PCA brochures and “cut-sheets” contributed to the airline and airport view that nothing needed to be done, because the existing designs could meet both the legislative requirements and also the performance issues.
R-22 PCA brochures and specification sheets have listed R-134a and R-407c as alternative refrigerants for years. What they have not said is that the 60-ton PCA shown on the R-22 data sheet will only provide 40 tons of cooling when operated on R-134a or that an R-134a unit that supplied 60 tons of cooling was about 30% larger and 20% to 30% more expensive. Refrigerants and performance issues related to an industry awakening to a new reality are detailed below.
Understanding Alternative Refrigerants
What alternatives to R-22 are legally acceptable and available? The government’s answer is: “Most are HFCs and include R-134a, R-404A, R-407C, and R-410A. In the United States, R-410A is the most popular choice for home air conditioners.” (http://www.epa.gov/)
Each refrigerant listed above has characteristics that determine its economic impact and technical acceptability for the preconditioned air application, which has relied on R-22 for the past 40 years.