As the industry explores alternatives to HCFC-22 in retrofit and new applications, the United States Environmental Protection Agency (EPA) has recently updated its own listing of “acceptable substitutes in household and light commercial air conditioning.”

The June 19 EPA report said, “Substitutes are reviewed on the basis of ozone depletion potential, global warming potential, toxicity, flammability, and exposure potential.”

The R-22 alternatives deemed acceptable by the EPA are identified by designations assigned by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) as well as some by trade names. The list also notes whether or not the alternative can be used in retrofit or new applications or both.

The following is the “acceptable substitutes for HCFCs (class II ODS) in household and light commercial a/c” and whether each is for retrofit (R) or new (N) applications or both. Here, the listings are arranged in numerical order.

• RS-44; R/N

• R-125/134a/600a; R/N

• R-125/290/134a/600a; R/N

• HFC-134a; N

• R-404A; R/N

• R-407A; R/N

• R-407C; R/N

• R-410A; N

• R-410B; N

• R-417A, ISCEON 59, NU-22; R/N

• R-421A; R/N

• R-422B; R/N

• R-422C; R/N

• R-422D; R/N

• R-424A; R/N

• R-427A; R

• R-434A; R/N

• R-507; R/N

• R-507A; R/N

• Ammonia absorption; N

• Evaporative/desiccant cooling; N

• KDD5; R/N

• THR-03; N

A Google search regarding KDD5 produced a copy of the Oct. 4, 2007 “Federal Register” in which the refrigerant was listed as an acceptable substitute for R-22 in such applications as chillers, industrial refrigeration and a/c, retail food refrigeration, cold-storage warehouses, refrigerated transport and ice machines as well as ice skating rinks and other applications. The EPA did note in that report that “the submitter of KDD5 has claimed its composition as confidential business information.”

A Google search for THR-03 did not produce information on the refrigerant. However, in the June 19, 2009 EPA report there was a note saying THR-03 in new applications “applies only to window-unit residential air conditioning, and not to central air conditioning systems.”

Publication date: 08/03/2009