Daimler Goes It Alone on R-744 For Automobiles

While all of the other car manufacturers around the world are scurrying towards the latest and newest fad of HFO refrigerants Daimler is stepping away from the pack and creating their own alternative refrigerant method for automotive air conditioning. If we look at the automotive market today we can see one primary refrigerant known as R-134a.

134a is an HFC refrigerant and is known for it’s extremely high Global Warming Potential number of one-thousand four-hundred and thirty times that of Carbon Dioxide. That means that any of this R-134a that is released or vented into the atmosphere actively contributes to Global Warming at a rate a thousand times more than Carbon Dioxide.

The rush was on to develop a new alternative refrigerant. Honeywell and Chemours offered a solution. They offered the new Hydrofluoroolefin refrigerant known as 1234yf. This yf refrigerant is non Ozone depleting and also has a minimal GWP of four. Automotive companies jumped at this new refrigerant as a solution to their problems. However, there was one company, Daimler, that was not in favor of this new refrigerant. Their reasoning was that this new refrigerant went up a scale on the refrigerant flammability rating. 134a was rated as a 1, or non-flammable. 1234yf was rated as a 2L, or mildly flammable.

To remove their doubts about this new refrigerant Daimler did numerous test scenarios to see how the refrigerant would react when the tank was ruptured and the refrigerant made contact with the hot parts of the engine. The test did not end well, in fact the refrigerant ignited causing a fire under the hood of the vehicle. There is a video of this that can be found by clicking here.

After this test result was released the rest of the world tried to replicate it, but no one was able to. After time the governments and companies dismissed the video and test as a fluke and stated that it was not reproduce-able. Since then the world has moved forward with 1234yf. In fact in the European Union 134a was banned entirely on new models. There is a similar ban coming to the United States in the year 2020. (2021 model years.) Throughout all of these changes Daimler fought and fought against companies and even against the European Union.

They wanted to continue using R-134a as they deemed 1234yf as unsafe. I won’t get into all of the details here but there was a large back and forth between Daimler, Germany, and the European Union. After years of debate and arguing Daimler eventually agreed to use 1234yf in all of it’s model ranges starting in 2017. To get around the safety issues that they saw with 1234yf Daimler developed their own innovations including a patented system to keep the fluid and hot engine components separated even in the event of an accident.

The Rise of R-744

Remember how I said that all Daimler 2017 models would be using 1234yf? Well, there is an exception to that. The S-Class and the E-Class models will not be using 1234yf and will not be using R-134a. No, folks. They will be using the first R-744 Carbon Dioxide automotive application. What is so amazing about this is that Daimler started working towards their own alternative clean refrigerant in January of 2014 and then just three short years later they already had models rolling out of the shop with it installed and ready to go. Talk about German efficiency.

This was no easy feat either. As most of you know CO2 operates at a much higher pressure then other refrigerants. CO2 was actually one of the first mainstream refrigerants to be used across the United States but it’s popularity waned due to the high rate of part failure and also due to the invention of CFC and HCFC refrigerants like R-12 and R-22. In order for Daimler to properly use CO2 for their cars they had to redesign nearly all of the components to accommodate the higher operating pressure. To give an idea of the pressure difference, CO2 operates around ten times the pressure of a regular system. So, that meant that they had to create a new compressor, evaporator, and condenser. That’s not even factoring in the new seals, hoses, o-rings, and everything else that was involved.¬†Frankly, folks I’m astonished at how they accomplished this. It makes me want to go out and by a Daimler vehicle… if only I could afford one.

Usually, when a company makes this kind of invention and progress on new technology they like to hold on to it and patent it so that they keep the competition’s hands off of it. Not Daimler. Nope. They have allowed other companies access to the designs and equipment used so that other OEs can more easily design their own CO2 systems. That is a stand up move by Daimler and really shows that they care about the safety of the drivers as well as the environment.


Now, you may remember from earlier that I said Daimler was using 1234yf refrigerant on most of their models in 2017. This was not their choice but they gave in after a long and hard fought battle. Well the good news here is that this yf usage from Damiler is only temporary. It was only because of the time crunch that they were under. On January 1st, 2017 R-134a was no longer acceptable in new vehicle models in the European Union. So, Daimler was practically forced to use 1234yf on their models. Their ultimate plan is to transition all of their vehicle models over to the new R-744 application but at this time they are just not quite ready yet. Don’t worry though I’m sure it will only take them a couple more years.

Regardless, I am just amazed at the speed and innovation that Daimler has done when faced with a new refrigerant that they felt was not safe for public use. Instead of towing the line like the rest of the OEMs in the world they decided to set themselves apart and make their own system. That alone speaks to the quality of Daimler.