An Update On R-22 Alternatives
Based on current EPA regulations related to emissive applications, production of R-22 is scheduled to be phased out in 2010 for new equipment and in 2020 for all other emissive equipment applications. New equipment using R-22 cannot be manufactured in the U.S. after 2010.
Note that R-22 used as a raw material in manufacturing (where refrigerant is transformed or destroyed) can continue to be produced indefinitely.
The effect of these dates is the following:
The selection of a particular R-22 alternative is complicated by two issues: first, the large number of applications using R-22, and second, the number and variety of substitutes available.
R-22 is a versatile refrigerant found in a wide variety of A/C and refrigeration applications and used in a wide range of operating temperatures. With such a versatile range, R-22 will be difficult to replace with only one fluid. Due to the difficulties of replacing R-22, a number of contenders are vying for parts of the R-22 substitute world, including replacement refrigerants such as R-134a, -404A, -407C, -410A, -417A, and -507.
There are basically two distinct market sectors evaluating R-22 replacements: new equipment OEMs and the retrofit sector.
NEW EQUIPMENTFor the OEM side of the market, some trends are beginning to emerge.
For residential and light commercial A/C, R-410A is currently the main contender. Larger A/C systems and chillers are using R-134a and -407C, with some R-410A activity in screw compressor chillers and rooftops.
Refrigeration equipment is being made to use R-404A, -507, and some with R-134a.
RETROFITSIn the retrofit market, almost all compressor and system manufacturers recommend that rather than retrofitting R-22 equipment, users service this equipment with R-22.
However, if a user decides to retrofit R-22 equipment, R-407C and -417A could be used for the retrofit of A/C units, while for refrigeration, R-404A and -507A are available.
Note: R-410A should not be used for retrofitting because its higher pressures prevent this refrigerant from being used as a retrofit.
Some parts of the world are phasing out R-22 sooner than the U.S. is. In Europe, for example, R-407C has taken a big role in A/C applications and R-404A/R-507 in refrigeration. The main reason for R-407C’s success there is its similarity in performance to R-22.
Two common questions arise from the use of HFCs in general and R-410A in specific. They are the use of POE oils and the high pressure of R-410A.
POE OILSMost HFC refrigerants use POE oils. This is done to ensure miscibility with the refrigerant and thus oil circulation back to the compressor for lubrication. A new OEM system will already have the required POE oil, but that is not necessarily true on a retrofit.
While in some systems, partially miscible oils would work well (no oil traps, relatively short runs, etc.), most equipment manufacturers recommend the use of miscible oil, such as POE. When retrofitting to an HFC, it is usually recommended to perform an oil flush. Most manufacturers provide an approved flushing procedure which should be followed.
Another issue mentioned with POE oils is their hygroscopicity, or attraction to water. When handling systems using POE oil, special care must be taken to avoid contact with the open air, especially in humid areas.
R-410A’S PRESSURESR-410A’s pressures are about 50% higher than R-22. This is why R-410A cannot be used as a retrofit fluid in R-22 equipment. This is also true for pressure gauges, recovery tanks, recycling units, disposable cylinders, etc.
In general, due to the pressure differences, equipment and storage devices must be designed to handle the higher pressure of R-410A.
New equipment is designed, rated, and approved by UL, ASME, building codes, etc., to handle the higher operating pressures that will be seen with R-410A. The safety factors used for pressure relief valves or rupture disks in disposable cylinders are as high or higher than those used previously with other refrigerants.
The same type of precautions we took with R-22 cylinders should be followed with R-410A cylinders. Ignoring or violating these common safety principles with any refrigerant could result in dire consequences.
The bottom line is that R-410A does not pose any additional risks to the user due to its higher pressures when used in appropriate applications with properly designed equipment.
The R-22 market is evolving continuously. By understanding the different refrigerant products available in the market, contractors and wholesalers can make educated decisions on different refrigerant products, thus providing a smooth transition through the R-22 phaseout.
Note: For additional information on personal protective equipment and safety, health, and environmental information, read and understand the appropriate material safety data sheets before handling any refrigerant.
Rolotti is Technical Manager, Refrigerants, Atofina Chemicals, Inc.
Sidebar: R-22 Replacement ReviewThe following offers a summary of the main points to be considered per refrigerant as a replacement for R-22:
R-22 — Recommended for service of R-22 equipment. Will be manufactured in increasingly lower quantities for service until 2020.
R-134a — Best for medium- to high-evaporative-temperature new equipment applications. Requires POE oil. Single component. Not appropriate for R-22 retrofits. Several manufacturers. OEM approved for a variety of applications.
R-410A — Current choice for residential A/C. High capacity. Not for retrofits due to higher pressure. Requires POE oil. Several manufacturers. Equipment must be specifically designed for R-410A since different components, controls, expansion valves, etc., are used. OEM approved for several applications.
R-407C — Similar pressures and capacities to R-22. Has a glide. Requires POE oil. Best choice for an A/C retrofit. Several manufacturers. OEM approved for several applications.
R-417A — Similar operating pressures to R-22. Significant capacity reduction, especially at low temperatures. Has a glide. According to manufacturer, it may not need POE oil. Limited suppliers.
R-404A/R-507 — Small capacity increase. Small pressure increase. Best choice for retrofitting refrigeration equipment. Requires POE oil. Several manufacturers. OEM approved for several applications.
Publication date: 09/02/2002