Outcome of the MAC Summit
This year’s MAC summit took place in Saalfeden (Austria) on 17 February and was hosted by the European Commission in collaboration with the California Air Resources Board. The summit was attended by about 150 participants, including policy makers/advisers from the EU Member States (and other parts of the world), industry representatives and experts (from auto and auto parts manufacturers), academia and NGOs.
The theme of this year’s MAC summit was ‘Phasing out HFC-134a from Mobile Air Conditioning in the largest car market in the world. The background was the EC proposal on fluorinated gases and mobile air conditioners (MACs) that would require (a) a phasing out of HFC-134a from MACs from 1 January 2011, (b) containment of leakage of HFC-134a, (c) compulsory leakage rate tests and (d) appropriate qualifications for servicing personnel.
Mr Koji Kikuchi, Vice-Chairman of JAMA’s MAC Working Group, presented JAMA’s position on the use of CO2 refrigerant systems, in light of the forthcoming EU regulation. The main points raised were:
- MAC systems with CO2 refrigerant: The use of CO2-based MAC systems is one of the main alternatives to HFC-134a systems. The principal advantage presented by this technology is the very low global warming potential (GWP) of CO2. However, these systems also present significant disadvantages (e.g. high pressure and low efficiency at high temperature) which give rise to such concerns as actual environmental performance, polarisation of refrigerants (manufacturing and infrastructure impacts for global operations), and actual vehicle performance (e.g. compressor power and safety).
- Impact on the environment: Two key concerns with respect to the environmental performance of CO2 systems are: (1) the increased compressor power of CO2 systems (under the same cooling performance) and (2) the actual impact of increased compressor power on vehicle fuel efficiency. A test with a 1.0-liter compact vehicle (urban mode, 30degC w/solar radiation, fresh air, maximum cooling) showed a 25% increase in fuel consumption.
Whilst it is true that CO2 mobile air conditioning systems perform better than HFC-134a systems with regard to direct emissions (i.e. refrigerant leakage), this is not the case for indirect emissions (power consumption). Current test data on TEWI (Total Equivalent Warming Impact) performance of both systems has shown that, overall (taking direct and indirect emissions into account), CO2 systems do not perform as efficiently as HFC-134a ones. This has proven to be the case in regions with high average temperature, including many parts of Europe. In other words, the overall global warming impact (direct and indirect emissions) of CO2 systems can actually be larger than that of HFC-134a systems. Thus, for many regions including certain parts of Europe, CO2 is not the most appropriate refrigerant.
- Impact on refrigerant polarisation: HFC-134a is not being phased out outside the EU (including USA and Japan). This will create significant obstacles for the sector (e.g. redesign of components, new additional parts, etc.) and adversely affect companies that operate globally, including European car manufacturers. Ultimately, it will negatively impact consumers.
- Indeed, CO2 is not seen as a global solution; furthermore, refrigerant polarisation would effectively duplicate the development and production of MAC systems across the globe and cause non-negligible infrastructure and servicing challenges in the aftermarket sector.
- Impact on vehicle performance: As mentioned above, CO2 systems would require an increase in compression power to achieve the required cooling performance. This in turn would negatively impact acceleration performance (increases in acceleration time of up to 48% have been recorded) and fuel consumption (between 8-12%). Given the refrigerant property (high pressure), it would also require pressure-proof structure which in turn will impact vehicle weight and costs. The installation of CO2 systems requires additional components that will need to be taken into consideration for installation flexibility and crash safety. The foregoing is a particular concern for compact vehicles, as consumers are likely to move away from that segment if fuel efficiency and overall power performance decline.
In summary, the three main problems associated with CO2 MACs are:
- There is no clear evidence that the environmental impact of CO2 MAC systems is superior to that of HFC-134a MAC systems.
- There would be a global disadvantage due to refrigerant polarisation (development, production and servicing).
- There are many unresolved issues that significantly impact vehicle performance (particularly that of compact vehicles).
Consequently, JAMA made two specific requests at the MAC summit:
- To evaluate the environmental performance of HFC-134a systems and CO2and other systems in detail and over their life cycle;
- To review the timing of a HFC-134a ban, based on the test results which will be available in 2007.