CO2/R744 SYSTEM REPAIRS & DIAGNOSTICS
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Note this service is only provided at the CoolCar Hamilton & North Shore branches.
SPECIALIST DIAGNOSTICS & REPAIRS FOR R-744/CO2 AIR-CONDITIONING SYSTEMS
R-744 is the refrigerant title for carbon dioxide (CO2).With the advent of parallel imported cars such as the high end Mercedes S-Class, car air-conditioning systems built for this refrigerant are beginning to circulate New Zealand.
R-744 air-conditioning systems are not installed into car's being sold directly into the New Zealand market, thus NZ Mercedes Dealerships does not have the necessary equipment required to diagnose or repair issues in these cars. CoolCar set about setting up two of our workshops with the gear, and the know how to repair these cars.
WHAT MAKES R-744 SO SPECIAL
To understand, it also helps to understand the term Global Warming Potential, or GWP:
GWP is a measure of how much heat a greenhouse gas traps in the atmosphere over a set period, (usually 100 years), compared with the same amount of carbon dioxide.
The GWP of carbon dioxide is equivalent to 1. Whereas the most common refrigerant used in vehicle air-conditioning systems is R-134a, which has a GWP equivalent to 1,430. This means CO2 is a much more environmentally friendly gas to use over your standard refrigerants, and that releasing 1 kilo of R-134a would have the same 100-year warming effect as releasing 1.43 tonnes of carbon dioxide.
Due to the dense nature of CO2, and its naturally high pressure-temperature relationship, R-744 air-conditioning systems must operate at much higher pressures than other refrigerants. Therefore, all parts incorporated in an R-744 air-conditioning system must be rated for operation and much higher pressures.
Despite being reinforced, the high pressure of the CO2, and wear, tear and corrosion just like in other cars, vehicle's using R-744 can still leak refrigerant. However, due to the low GWP of CO2, this is much less taxing on the environment than the equivalent of release of R-134a.
R-744 however, can be dangerous. It is non-flammable, but due to the high operating pressures inside the system, it must be handled carefully. Recovering refrigerant, diagnosing and repairing leaks in these cars poses a safety risk. However, our technicians are thoroughly educated on the hazards, and use the specialised equipment and personal protective equipment when diagnosing and repairing R-744 air-conditioning systems to ensure the safety of our technicians and your vehicle.
WILL R-744 BE INTRODUCED AS THE STANDARD?
R-744 Is steadily being introduced into production vehicles. Mercedes introduced the Mercedes-Benz S400 Coupe, in 2016-2017 as one of the very first complete and working models. And is now found in both their S-Class and E-Class ranges. However, they have reportedly stopped pursuing R-744 as of 2021. Likely due to the cost, and lack of specialised repairs available for the new tech.
This does not spell the end for R-744 systems however, as Volkswagen, Skoda and Ford are now using R-744 technology in their latest models. Its use is expected to grow as manufacturers develop the tech and repair know how.
