Today, the chemical HFC-134a is used in car air conditioning, and is making global warming worse. That is why it is being phased out, starting from 2011, in the EU with more countries expected to follow.
Several alternatives exist to replace this refrigerant. None are perfect. However, CO2 Technology appears as the most sustainable and cost-effective solution, with a potential to reduce total car emissions by 10% alone.
CO2 Technology is the best insurance policy worldwide against future climate change legislation, as the refrigerant CO2 will not need to be phased out.
The decision for the next generation car air conditioning refrigerant hinges upon 3 key issues.
Namely, which refrigerant is;
Over the life cycle CO2 systems can bring about more cost savings than the alternatives. Thanks to fuel savings and cheaper servicing, an initial higher investment (i.e. 20€ per unit for car manufacturers) can easily be recovered.
How does CO2 Technology work?
Today CO2 is released as an industrial waste product directly to the atmosphere. By cleaning and re-using it for cooling and heating a car, i.e. recycling it, this CO2 can become environmentally neutral.
By contrast, competing chemical alternatives have to be manufactured from scratch with all accompanying environmental burdens.
CO2 can either be directly released to the atmosphere, contributing to global warming, or recycled for refrigeration, thus becoming environmentally neutral.
The risks of the proposed new chemical refrigerant
A new chemical refrigerant proposed by DuPont and Honeywell, HFO-1234yf, presents a large number of unsolved issues: its long-term effects are unknown, it leads to lower efficiency, and it will create incentives to extend the lifespan of highly polluting R-134a.
Moreover, it is flammable.
Concretely, these are the main risks:
1) Unknown effects:
The impact of HFO-1234yf on the environment is insufficiently known.
The influence of the decomposition product Trifluoroacetic acid, CF3C(O)OH or TFA (a herbicide),
on biodiversity is not understood. As a result, the long-term consequences for the environment
are uncertain. Furthermore, it is not clear whether the substance is toxic, as independent testing has not yet been carried out. The fact
that certain refrigerants were creating the Ozone Hole, and later contributing to Global Warming,
was discovered only years after these refrigerants were on the market.
2) Poor efficiency: The substance has lower efficiency than R-134a and therefore leads to higher indirect CO2 emissions. This was proved during the extensive tests carried out by Japanese car manufacturers, as well as by General Motors, across entire vehicle fleets. Implementing HFO-1234yf in new cars would decrease the efficiency of MAC systems by about 5-7% compared to today’s standards. This will increase a vehicle’s overall fuel consumption by 7%. As a result, greenhouse gas emissions will increase instead of decreasing.
3) Retrograde step: It is claimed that HFO-1234yf facilitates the industry transition to new MAC systems. In reality, it will do the opposite. HFCR-134a costs approximately 5 €/ kg, whilst it is expected that HFO-1234yf will cost 50€/KG, ten times more. Consequently, after the first charge of refrigerant HFO-1234yf has been expended, consumers are highly likely to refill their MACs with R-134a as a cost saving measure. The prohibitively high cost of HFO-1234yf will prove to be an even greater impediment in developing countries where the car market is exponentially growing. HFO-1234yf has a global warming potential (GWP) of 4, whilst R-134a has a GWP of 1430. The use of HFC-134a will be uneccessarily prolonged by the introduction of HFO-1234yf into the global market, therefore undermining the ultimate goal of reducing greenhouse gas emissions.
4) Flammability: As independent tests have shown, in case of a front-end accident, systems using HFO-1234yf would significantly increase the risk of fire in the passenger cabin. This new refrigerant hence reduces today’s safety level of MAC systems, as it puts human life at risk. Additional safety measures would thus be necessary to mitigate this risk. This would have a negative impact on the system’s efficiency, while increasing its costs at the same time.
How flammable is it?
Tests October 2008 (DUH):
Video documentary by DUH - Flammability testing of 1234yf (in English, running time: 8 min 26 sec)
Background: Moderated by transport expert, Dr. Axel Friedrich, this video documentary refers to the investigation
by DUH of 1234yf compared to the currently used R134a, at normal driving conditions when the engine of a mid-sized
standard car reaches certain temperature. An accident or small collision is simulated, resulting in the rupture of a
hose in the system. The refrigerant then escapes and enters into contact with the engine. While nothing happens in
the case of R134a, when 1234yf is tested, the refrigerant ignites immediately, leading to a fire in the engine
compartment. If the fire is not stopped, it extends and can reach the passenger cabin. Highly toxic gases result
from the refrigerant burning.
After tests simulating front-end accidents, this is what would happen 1:
Video 1: at 970° C
Video 2: at 800° C.
Video 3, at 600° C
Video 4, 1234yf Canister Test
Image gallery:
1 The rupture of certain lines and components, as a result from such type of
accidents, leads to the release of a mixture of refrigerant and oil into the engine compartment.
This in combination with oil circulating in the system leads to the release of a flammable
mixture of refrigerant and oil onto hot engine parts, which can then easily ingnite.
More information on: http://www.r744.com/article.view.php?Id=375
