Another refrigerant

Cars built after about 1993 use a refrigerant that is not a CFC. This is called R134a and saves using a name that is about as long as a certain Welsh railway station. There should be a sticker in the engine bay telling you if you have R134a. This is an HFC.
There are many other refrigerants, many of which are based on inflammable gases but obviously these cannot be used in a moving vehicle (imagine a crash, the front radiator could be at 300 psi full of something like butane and has just had a small hole punctured in it - WW2 flame-throwers could learn a thing or two from this). Both R12 and R134a are not flammable. Although R12 is no longer fitted into new cars those built before about 1993 will still need to be recharged with it, or with a substitute, say every three years.
A fact not always appreciated is that R12 is so efficient that it needs lower pressures to achieve the same result and thus creates fewer greenhouse gases than R134a.

R134a systems are becoming more and more efficient as developments occur so are becoming smaller, contain less refrigerant, use even less fuel to run and have lower losses. Nevertheless the powers that be in the UK and Europe are legislating that the use of R134a be phased out in the next few years to be replaced by a new refrigerant.. The front runner for this refrigerant in Europe is called R744 and is actually Carbon Dioxide, CO2, used at very high pressures. The technology to achieve this in test vehicles is already here, indeed I saw a demonstration vehicle in Frankfurt in September 2004, but it is likely that it is going to be about four years before the first production models start arriving in the showrooms but by 2011 all new models must use a new refrigerant and by 2017 every new car must use it.

If Europe does decide to go-it-alone with R744 (the USA and Japan have indicated that they do not intend to use R744) the repair and recharging of this refrigerant are going to be much more complex. The pressures needed to make this system work efficiently are considerably higher than for R134a, extending into the thousands of pounds per square inch rather just into the hundreds. Inevitably this is creating tehnical problems that need addressing.

There are however interesting offshoots that are possible from using this refrigerant that are more acceptable than from R134a such as the ability to have the heater going full blast within a few seconds of starting the engine by means of using the AC system as a heat pump. This may not sound too important but already diesel engine technology has advanced so much that there is very little waste heat to utilise in the car's heater system and the manufacturers are having to include a supplimentary heater burning diesel (like a mini central heating boiler) to provide enough heat for the occupants comfort. Petrol engines will surely progress to a similar level of efficiency in time.

New evaluations of the the impact on global warming of R134a and R744 presented in July 2005 showed that the long term results of R744 were in fact considerably inferior to that of R134a but as government dislike changing their minds I suspect that we are going to be stuck with R744 in Europe for the future.

I find it fascinating that all this inter-governmental activity to remove from refrigerants this one element (generally called the F-gas) in an effort to 'Save the World' is the same element that we deliberately add to our toothpaste and even add to our drinking water to help save our teeth. Strange, ain't it?

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