Major changes to automotive airconditioning systems
Major changes to legislation will see the ensuring automotive air conditioning industry standard refrigerant, R134a, phased out of use in new vehicles over the next few years.
As is taking place in the European Union and United States, the HFC phase-down will accelerate, and eventually mandate, the switch to low-GWP refrigerants in the air conditioning systems of new vehicles.
In fact, a growing number of vehicles imported to New Zealand and Australia from markets where a phase-down is in place are already on our roads and the end of local car manufacturing this year will add momentum to the uptake.
Since the ozone layer damaging CFC refrigerant R12 was phased out in the mid-1990s, the only refrigerant used by vehicle manufacturers has been R134a.
With climate change now on the agenda, vehicle air conditioning systems using R134a are becoming a thing of the past because R134a is around 1,300 times more potent than carbon dioxide as a greenhouse gas if released to the atmosphere.
For comparison, R12 is 10,900 times more potent than carbon dioxide as a greenhouse gas, in addition to destroying stratospheric ozone.
Both R1234yf and R744 are ozone-friendly, and have global warming potential of below or equal to carbon dioxide.
Much of the global automotive industry has adopted R1234yf as the standard refrigerant in new cars, primarily due to tightening overseas legislation over the global warming effect of refrigerants released into the atmosphere.
Unlike the switch from R12 to R134a there will be no need to change existing air conditioning systems over to R1234yf, because R134a will continue to be available for servicing older equipment.
Due to similar thermal properties between R134a and R1234yf, faults with systems using the new refrigerant can be diagnosed using the same methods as R134a.
R1234yf carries an ASHRAE rating of A2L (mildly flammable) and is subject to Dangerous Goods class handling and transportation requirements.
However R1234yf is not easily ignited and struggles to sustain and propagate a flame compared with A3 (highly flammable) rated refrigerants available to the aftermarket but never used or approved by OEMs.
To ensure safety, new SAE standards apply to the quality of system components and the equipment used to service R1234yf systems. Some equipment is rated as compatible with both R134a and R1234yf and some equipment is suitable only for R1234yf.
Mercedes-Benz parent company Daimler and Volkswagen Group have developed systems using a carbon dioxide as a refrigerant (named R744) that will initially be used for high-end vehicles.
R744 requires operating pressures up to 10 times higher than R134a or R1234yf.
Back street regassing will soon be a thing of the past. Picture Wikipedia/ Mike Peel (www.mikepeel.net).