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Executive director of communications and editorial at the Automotive, Air Conditioning, Electrical and Cooling Technicians of Australasia (VASA), Haitham Razagui, gets a first hand look at the world's first Co2 air conditioning system.

Just as you were getting your head around the latest automotive air-conditioning refrigerant, R1234yf, another one crops up on the scene.

Last September I was at an auto-AC conference in Frankfurt, where a prototype Mercedes-Benz S-Class using carbon dioxide as air-con refrigerant was being demonstrated.

The refrigerant name for CO2 is R744. It behaves very differently to the synthetic gases we’re used to, operates at seriously high pressure and can form dry ice if you’re not careful.

Beneath the gleaming black S-Class bonnet, among what looked like desert sand – evidence of hot-weather testing – I spotted a Sanden R744 compressor and some Valeo heat exchangers plumbed around the V6 turbo-diesel engine.

Now Sanden has officially announced it is supplying Mercedes-Benz parent company Daimler with “the world’s first CO2 compressor for mass-produced passenger cars.”

The global media launch for the facelifted Benz flagship took place in Switzerland in July, with six-cylinder engines moving from V6 layout to inline format. So I take it the prototype in Frankfurt was a proof-of-concept machine and that testing of the straight-six engines with CO2 air-con components came later.

Indeed, the announcement from Sanden suggests the development timeline for this technology was compressed.

“It has been quite a challenging project also for Daimler to get the R744 AC system launched in such a short period,” said Daimler AG project leader for R744, Ralf Theurer.

He added that the reason for selecting Japanese component manufacturer Sanden as development partner for Daimler’s CO2 air-conditioning systems was “their extensive experience with this refrigerant and pioneering spirit towards new technologies.”

According to Sanden it accelerated the development for Daimler by drawing on its experience in R744 applications including freezers, refrigerators and vending machines, then incorporated technologies from all these products to create a high-performance automotive compressor.

“Therefore the strategic partnership with Sanden has been very important and we are pleased about this successful launch,” Dr Theurer said.

Sanden Automotive Components took the development of this R744 compressor incredibly seriously, establishing a project team that reported directly to the company president, in close collaboration with their German counterparts at Daimler.

Company president President Tsuguo Ito said he intends to expand this technology and use the knowledge gained throughout the development to grow in a sustainable manner in the world market.

The R744 compressor has a 31cc capacity, a fifth of the R134a unit it replaces, but Sanden claims its cooling performance and function exceeds conventional compressors.

Its packaging and weight is also said to match that of the old R134a compressor and it is able to withstand five times the operating pressure. Sanden also says the new R744 pump included internal design features designed to reduce noise, with new control technology that improves its stability and safety.

Facelifted S-Class limousines are now literally driving themselves off the end of the Sindelfingen production line just outside Stuttgart, travelling 1.5 kilometres to a holding yard without anyone behind the wheel.

They are obviously pretty capable of avoiding accidents, but if you see one in your panel shop, don’t be surprised to find a pretty alien-looking AC system to recommission.

I’m travelling back to Frankfurt next month (September) for the international motor show, and will bring back updates about which R744 cars are coming to Australia, and when, from the people in suits at each German car manufacturer.

Watch this space.

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