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HFC-152a as an alternative to HFC-134a in mobile air conditioners
Background
All passenger vehicles and light trucks manufactured with air conditioning (A/C) worldwide currently use refrigerant hydrofluorocarbon 134a (HFC-134a) in direct expansion systems. European Union (EU) regulations require air-conditioned vehicles sold in EU countries to use refrigerants with global warming potentials (GWP) less than 150 beginning in 2011 for new type vehicles and in all vehicles by 2017. GWP is an index comparing the climate impact of an emission of a greenhouse gas relative to that of emitting the same mass of carbon dioxide (CO2).
The predominant refrigerant in today’s A/C systems, HFC-134a, has a 100-year GWP of 1430 (based on the most recent Assessment Report of the Intergovernmental Panel on Climate Change – http://www.ipcc.ch/) and is therefore being phased out under the EU legislation described above. Vehicle manufacturers prefer a single global refrigerant that satisfies regulatory authorities in all global markets. Numerous alternatives have been proposed. Systems satisfying the EU regulation using carbon dioxide (R-744), and HFC-152a (R-152a) have been engineered and tested, and component and systems suppliers have announced their commercial availability. Additionally, global chemical manufacturers have developed and are currently testing new refrigerants that meet the GWP 150 limit.
Benefits of HFC-152a
The following report is the result of the EPA workshop on HFC-152a secondary loop vehicle air conditioning systems, held August 14-15th, 2007, in Washington D.C.. It documents the environmental benefits of and engineering safety strategies for mobile air conditioning systems that use HFC-152a as a refrigerant. The conclusion is that HFC-152a can be safely used in secondary loop A/C systems that keep refrigerant out of the passenger compartment, and that HFC-152a used in secondary loop can offer fuel savings, cost savings, and environmental benefits.
Designing Efficient Secondary Loop HFC-152a Systems
The following report document designs strategies to optimize the efficiency of secondary loop HFC-152a systems.
Read the full report: PDF