When it comes to vehicle emissions, carbon dioxide (CO2) is generally the problem that carmakers are looking to solve: attempting to reduce the amount of CO2 emitted from their exhaust pipes. However, now CO2 could actually be the solution rather than the problem.
That’s because Volkswagen has announced it will use CO2 as its low global warming potential refrigerant for mobile air conditioning systems.
The German carmaker says it will roll out CO2 MAC (mobile air conditioning) systems over its entire vehicle fleet. Known as R744, the refrigerant has a global warming potential value of just “one”: and is 99.3 per cent below the EU’s specified limit of 150 for MAC systems. By comparison, R134a, which is currently used most widely for MAC systems, has a global warming potential of 1,300 according to figures from the US Environmental Protection Agency.
Reducing emissions from mobile air conditioning systems has been investigated since the late 1990s with air conditioning systems producing the equivalent of 7g/km of CO2. At one point it appeared that R1234yf would be the chosen refrigerant. However, in September last year, Daimler said its internal testing identified safety issues in certain conditions and decided against using the refrigerant in its products: with BMW and Volkswagen following its lead.
CO2 has now been chosen by Volkswagen because it is seen as an A1 refrigerant that boasts minimal toxicity while not being flammable. It also has the least impact on the environment and is available with the required qualities needed for mobile air conditioning systems at extremely low costs.