24 June 2014


This paper provides an overview of the Air-Conditioning, Heating, and
Refrigeration Institute (AHRI) research activities on heat pumps. During the past few years, AHRI has conducted research projects covering refrigerants testing, risk assessment of mildly flammable refrigerants, and Life Cycle Climate Performance (LCCP) of residential heat pumps. Several low-GWP alternative refrigerants were tested for heat pump applications in
the AHRI Low-GWP Alternative Refrigerants Evaluation Program (Low-GWP AREP). The tested refrigerants aimed at replacing R-410A are classified as A2L, according to ASHRAE
Standard 34. This paper also summarizes AHRI’s study on the risk assessment of residential heat pump systems using A2L flammable refrigerants. The potential ignition risks of R-32, HFO-1234yf, or HFO-1234ze in a ducted residential split heat pump system during operation and servicing are presented. Finally, the development of an AHRI tool to evaluate heat pumps’ LCCP is introduced. The tool can be used to evaluate residential heat pumps direct
and indirect emissions over their life time when using different refrigerants in different geographical regions.