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Mobile air conditioning. The life-cycle costs and greenhouse-gas benefits of switching to alternative refrigerants and improving system efficiencies.

Author(s) : BLUMBERG K., ISENSTADT A., TADDONIO K. N., ANDERSEN S. O., SHERMAN N. J.

Type of monograph: Report

Summary

Motor vehicle air conditioning systems, also known as mobile air conditioning (MAC) systems, are a significant source of greenhouse gas (GHG) emissions. The fuel used to run MAC systems has been estimated to be 3–7% of that used by the global light-duty fleet, but MAC use can account for up to 20% of fuel use in congested and hot, humid climates (Chaney et al., 2007; Yang et al., 2018). In fact, GHG emissions associated with MAC systems are dominated by indirect emissions, emissions of CO2 associated with the energy required to run the AC system, which account for about 81–88% of the GHG emissions. The direct emissions that make up the rest are associated with leakage of the refrigerant used in the system. For this paper, we collected recent data and estimates available on alternative refrigerants—R744 (CO2) and R1234yf, both with GWP of 1, and R152a, with a GWP of 138—as well as on technologies that reduce MAC energy requirements. We examined all three alternative refrigerants as well as the current leading refrigerant, R134a, in both direct expansion (DX) and secondary loop (SL) configurations, employing load reduction and powertrain optimization strategies, for use with single or multiple cooling points and in different climates. SL systems are an alternative configuration to the DX systems in current use. While they reduce the overall system efficiency, SL configurations can provide other benefits, including reduction of direct emissions and costs. And while all refrigerants were considered in both DX and SL systems for comparison sake, SL offers safety improvements that are assumed to be required for the more flammable R152a.

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Pages: 70

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Details

  • Original title: Mobile air conditioning. The life-cycle costs and greenhouse-gas benefits of switching to alternative refrigerants and improving system efficiencies.
  • Record ID : 30026742
  • Languages: English
  • Subject: Regulation
  • Publication: Icct (international council on clean transportation) - - United states
  • Publication date: 2019/03