After Verheugen’s confirmation of 2011 deadline - What choices are left?

By team, Jul 22, 2009, 12:16 10 minute reading

After EU Industry Commissioner Verheugen put a final end to the debate about a potential delay of the 2011 MAC Directive deadline, automakers are left with either collective non-compliance, or a choice between CO2 and HFO-1234yf. has analysed the alternatives, their risks & benefits.

In a letter sent to European Parliamentarian Chris Davies early July and seen by Reuters, EU Industry Commissioner Günter Verheugen has renewed his commitment “to ensure that the objectives of the legislation on mobile air conditioning systems are fulfilled." After months of lengthy debates on whether the car industry would be in the position to comply with the low-GWP refrigerants directive, after an official clarification by the European Commission, after attempts by the European car manufacturers association ACEA to delay the deadline, and Verheugen’s reconfirmation, carmakers selling passenger vehicles in the EU after 2011 are now left with three main choices:
  • R744 / CO2: The natural refrigerant suggested more than a decade ago for use in MAC has been proven in real life to work efficiently and safely. For the moment, however, the further development of car air-conditioning systems using CO2 as refrigerant has been suspended because of the lack of commitment by the car manufacturers. After German carmakers committed to R744 in 2007, 2008, and 2009, there is no further action taken on their side to advance its research and serial production. On the contrary, all orders with German R744 suppliers have been stopped until a decision is taken.
  • HFO-1234yf (HFC): This chemical HFC refrigerant, presented in 2007 and widely discussed over the last months, has mainly dominated headlines with pending safety issues, including unsolved toxicity and flammability issues. Claims of a higher energy efficiency as compared to R744/CO2 and an easy drop-in solution making the switch from R134a more cost-competitive are up for discussion. No concrete orders have been made.
  • Non-compliance (R134a): The European car industry could stand in unison against the EU MAC Directive by simply ignoring the 2011 deadline. After the European Commission has made clear that there will not be any exemptions allowed for single EU states that could lead to a distortion of the harmonised internal market, car manufacturers could still continue pointing to the technical barriers they are facing when introducing new technology. The use of R134a after 2011, the first year to phase out the currently used refrigerant under the MAC Directive, is a willingly accepted non-compliance with union law that could imply legal and/or financial consequences. More importantly, if OEMs get away with simply not acting within legal frameworks, this would undermine the EU system of rulemaking, and affect the credibility of EU lawmakers in future initatives to lower global greenhouse gas emissions. As a final point, the prolonged use of a high global warming refrigerant just recently found to be a major source of HFC emissions worldwide could lead to catastrophic, yet underestimated impacts for the climate. For the sake of completeness, the below refrigerant comparison therefore takes also R134a into account.
The alternatives at a glance

The decision for one of the three alternatives R744, R134a, and HFO-1234yf (HFC) is depending on four main factors: costs, safety, environment, and performance. The overview sums up the scientific knowledge as of today:

* Not enough information available for carmakers to make an informed choice.

1 Flammability test results for R134a, HFO-1234yf, R744 - Obrist Engineering, 02/2008 / At 600°C, HFO-1234yf ignited when in combination with oil. Even when using a thermal shield, the refrigerant-oil mixture was ignited at 800 °C - SAE peer-reviewed paper “Safety Issues in the Application of a Flammable Refrigerant Gas in MAC Systems: the OEM Perspective” (Monforte, Caretto), 01/209 – currently under revision.

2 AIHA WEEL (Workplace Environmental Exposure Levels Committee) assignment for HFO-1234yf: The maximum exposure level to HFO-1234yf at the work place was lowered to 400-500 ppm. The primary reason is the unexplained increased mortality seen in adult pregnant rabbits at 5500 ppm. There were deaths in rabbits at 5500 and 7500 ppm and 10,000 ppm in the developmental toxicity studies, HFO-1234yf did not induce developmental effects at concentrations below those that induced maternal effects. Recommended WEEL Guide for exposure to HFO-1234yf:  500 ppm as an 8-hour TWA. // Formation of Hydrogen fluoride (HF): 1kg of HFO-1234yf creates 700 grammes of HF. SAE peer-reviewed paper “Safety Issues in the Application of a Flammable Refrigerant Gas in MAC Systems: the OEM Perspective” (Monforte, Caretto), 01/209 – currently under revision.

3 Observed issues with the stability of the HFC (HFO-1234yf) in the system. Greenpeace 2009: lubricants (PAG oils) break down to HF in contact with HFO, a clear indication of the low stability and therefore high reactivity of the substance. / Honeywell, DuPont 2008: a special oil is required due to the synthetic refrigerant’s miscibility and stability. // Stability in the atmosphere is low.

4 The production of HFO-1234yf MAC systems might require special explosion-proof production charge equipment. In general, classified as “highly flammable” by EU legislation, HFO-1234yf would be subject to ATEX level 2 management, where throughout the whole value chain from production to recovery anti-spark equipment would be needed. Similarly, for servicing, spark-free tools could be a minimum requirement.

5 GWP for 100 years: R134a = 1420, HFO-1234yf (HFC) = ~4, R744 = 1 / GWP for 20 years: R134a = 3590, HFO-1234yf (HFC)
» 4, R744 = 1

6 The GREEN MAC LCCP model 2009 (ARCRP II) has shown that R744 outperforms R134a in most conditions worldwide. Other comparisons between HFO-1234yf and R134a have indicated that HFO-1234yf will show a similar performance or will be 5% less efficient than R134 when used as a mere drop-in solution without system modifications (SAE World Congress 2009 Honeywell). Therefore, it can be concluded that R744 would also outperform HFO-1234yf when calculated with the global GREEN MAC LCCP model.

7 The HFC 1234yf is a Volatile Organic Compound (VOC), decomposing close to the earth surface (cities) into TFA. VOCs are gases or vapours emitted by various solids and liquids, many of which have short- and long-term adverse health effects. // Furrer 2008: Trifluoroacetic acid (TFA), a decomposition product of R134a and HFO-1234yf, will be leached out from the atmosphere by the rain, developing a herbicide effect. The effects on the earth’s ecosystem are still unknown as the eco-toxicological potential of TFA has only been evaluated to a small extent. The strong organic acid TFA will remain stable in the nature over a long period due to its low decomposition potential. // Greenpeace study 1998: 19 different products containing fluorine forming from R134a, some potentially highly reactive and toxic.

8 If used as a drop-in solution, the HFC refrigerant 1234yf systems have the potential to be refilled with more cost-effective R134a, increasing the environmental burden through a GWP of 1420. The risk is considered to be especially high in developing countries. Additional safety measures applied to the system to impede a misuse are likely to raise the system costs again.

9 Visteon 2008: HFO-1234yf will not be a drop-in solution, which would require extra costs besides the refrigerant itself. / Based on announcements by chemical companies, the cost of the refrigerant would range at $35; another $25 would be needed for the system. In addition, there will be extra costs for safety equipment avoiding hazards with a flammable / explosive refrigerant in the assembly plant, as well as costs arising from modifying the system to avoid a refill with R134a. / SINTEF 2007: Initial costs for implementing R744 MAC are estimated to be less than €30. This cost is offset by annual savings of €50 due to saved petrol.

10 Refrigerant costs of HFO-1234y could be more than 10 times higher than those of R134a. The costs for R134a at around €5/kg have increased in 2007-2009, due to escalating raw material costs, such as a 500% price increase in sulphuric acid in 2008. In addition there are energy and freight costs to transport the chemical refrigerants, as opposed to global availability of CO2/R744. F-gases legislation, including the F-gases regulation in the EU asking for improved system design, containment, recycling training etc. will require additional investments due to compliance costs. The refrigerant cost for R744 is at 50 cents per kilo.

11 The servicing of R744 systems will be more cost-efficient since recovery of the low global warming refrigerant is unnecessary making sophisticated refrigerant handling equipment oblivious. In addition, more and more requirements to increase recovery and recycling rates will raise the end-of-life costs for R134a. If HFO-1234yf remains in the category of “highly flammable” in the EU, spark-free tools for servicing could be a minimum requirement. The increased costs for storage and distribution would further raise the cost of HFO-1234yf.

12 Production readiness for the 2011 deadline can be questioned for the proposed HFC refrigerant (HFO-1234yf). Ongoing safety tests, remaining REACH analysis in the EU, and a missing SNAP approval in the USA will delay the start of serial production. / OEMs presenting at the SAE World Congress April 2009 confirm that toxicity tests are not yet finalised. All OEMs part of the SAE 1234yf working group agree that more testing is needed to find out what needs to be done to make the thermal shield more effective and prevent igniting a HFO-1234yf-oil mixture at 800°C. Crash tests will need to be repeated with extreme under bonnet temperatures to demonstrate that the crash scenario is not to be considered of concern due to the extremely turbulent environmental conditions in which the leakage caused by the refrigerant circuit rupture would occur. A survey at the VDA Winter Meeting 2009 about the technological maturity, the production readiness and safety of HFO-1234yf in face of the approaching 2011 EU regulation deadline unveiled the industry’s scepticism, with 70 and 78 respectively out of a total of 99 respondents missing a proof that HFO-1234yf could comply with all requirements.

13 Research on R744 in MAC has been going on for more than a decade. Several system and component manufacturers worldwide confirm readiness for serial production.

14 R744 is more efficient that other refrigerants in 95 % of all driving conditions and saves up to 0.5 litres fuel per 100 km. HFO-1234yf has been found to show a 5% reduced performance when used as a drop-in solution in an existing R134a system. With enhanced heat exchangers and an optimised system, HFO-1234yf will show a similar performance as R134a.

15 The safe use of HFO-1234yf in next-generation hybrid and electric vehicles with Li-Ion batteries can not be automatically assumed. In 10 ignition scenarios involving HFO + oil, 6 lead to ignition, including one when using a thermal shield. Similarly, 9 out of 12 potential sources of ignition – among them fuses, electric motors, power switches, lamps, and batteries – led to ignition of HFO at above 800°C. A battery short circuit in an electric vehicle would generate enough power for ignition. Based on these facts, an OEM deliberately deciding in favour of HFO-1234yf could face legal consequences - SAE peer-reviewed paper “Safety Issues in the Application of a Flammable Refrigerant Gas in MAC Systems: the OEM Perspective” (Monforte, Caretto), 01/209 – currently under revision. / Survey results at the VDA Winter Meeting show that R744 is considered to be the best alternative candidate to develop an efficient heat pump function requested in plug-in electric hyprids and EVs. A future use of R744 systems operating in a reversed cycle in both heating and cooling mode will further reduce costs while at the same time providing additional comfort and safety for the driver.


By team (@r744)

Jul 22, 2009, 12:16

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