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Debate about air conditioning refrigerant R1234yf heats up

Debate about air conditioning refrigerant R1234yf heats up

By Andrew Marsh, 18.02.13
Posted in: Materials & Engineering | Public

The latest refrigerant R1234yf is deigned to significantly reduce the global warming potential of refrigerant gas compared to the current industry standard, R134a. This is the main drive to adoption of this refrigerant, which has the advantage of using similar system materials (pipes, hoses, sealing rings) to R134a system, whereas the EU proposal of CO2 based refrigerant AC systems would require a complete re-think. For the record, CO2 has a Global Warming Potential (GWP) of 1 – in that the systems use CO2 taken from the atmosphere and if they leak simply return into the atmosphere.

  • R1234yf has a GWP of around 4 – breaks down to constituent gases in less than a week.
  • R134a has a GWP of around 1440 – breaks down to constituent gases after 13 years.
  • R12 has a GWP of 8500, whilst R11 has a GWP of 4000 – both break down to constituent gases after 150 years.

The current status of air conditioning refrigerant in the European Union is that after 1st January 2011 no new types of vehicle would be type approved with refrigerant with GWP greater than 150, and no new vehicles could be sold with such refrigerant after 1st January 2017. Whilst R134a production is now only possible to manufacture for research purposes, there is no limit to re-cycling R134a until 31st December 2014.

So, why the fuss?

Mercedes-Benz circulated research which showed that during frontal offset impacts the AC system was punctured, and refrigerant (R1234yf) escaped close to ordinarily hot parts – ie, the engine exhaust manifold.  The result was ignition since R1234yf has a minor butane component, which then allowed other components of the refrigerant to form very toxic substances. The research was circulated amongst manufacturers during the summer of 2012, and Mercedes-Benz then made a public statement in September 2012.

The group of manufacturers tasked with assessing the impact of R1234yf studied the results, and some members tried to replicate the test – without success. Meanwhile in 25th September 2012 Mercedes-Benz recalled 3500 units of the B class W246 built with R1234yf to be replaced with R134a, and halted the R1234yf implementation programme.  Shortly after that BMW and Volkswagen Group joined Mercedes-Benz for the re-start of R134a production. On the 6th February 2013, BMW formally left the major group of R1234yf supporters, citing that the vehicle manufacturer working group test methods could not attain the safety standards BMW require.

The fact remains – R134a gave a significant reduction in global warming potential compared to refrigerants used the in the automotive sector before 1991, which was compounded by the requirement to have far greater joint integrity that ever before. The effect is that refrigerant rarely leaks over a number of years, whereas before 1991 it was common practice to re-fill vehicle AC systems every few years. In addition, with enough heat, almost any refrigerant will burn since the compressor oil which is entrained in it will ignite.

Finally – an awkward point. Mercedes-Benz effectively have made public the AC systems on some of their vehicle will rupture during impact. Volvo and the (late) Saab, for example, did not allow any AC system leakage after impact. There is no legislation on this point, but an interesting contrast between different manufacturer test standards.

What will happen?

  • A small group of vehicle manufacturers will try to overturn the banning of R134a.
  • The majority of vehicle manufacturers will follow either way.
  • Both R134a and R1234yf are likely to be in the vehicles from new for many more years.

For repairers: R1234yf will become more common on new cars until 2015, but not universal. The impact will be to maintain two sets of AC recovery station (or a single dual purpose unit).

For insurers: Roll out of R1234yf has not been clean cut, with many new types of vehicle launched in 2011 an well as 2012 fitted from new with R134a. Care should be taken to ensure vehicle manufacturer give up to date information about which models have R1234yf, and from which build date. In addition, the unit cost of R1234yf is notably higher than R134a, although this is mitigated by the modest quantities of refrigerant used per vehicle.

To read more, click ‘AC refrigerant – what next and when?’


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