Liebherr supplies CO2 air-conditioning systems to Siemens Mobility

Korneuburg (Austria), August 2025 – Liebherr-Transportation is delivering heating, ventilation and air-conditioning (HVAC) systems that use the climate-friendly natural refrigerant R744 (CO2) for the first time. The HVAC system is one of the first product solutions of its kind in mainline passenger transportation to be used in regular operations in Europe. The units will be installed on the roof of the Nightjet and Railjet new Generation from ÖBB, manufactured by Siemens Mobility, which will be delivered to the Austrian operator through the first half of 2028.

"We are very proud to be one of the pioneers in Europe with our product solution and to be able to contribute significantly to more environmental-friendly passenger transportation," says Dr. Klaus Schneider, Managing Director and Chief Technology Officer at Liebherr-Aerospace & Transportation SAS. "Our HVAC systems have been extensively tested and series production has successfully started at our Liebherr facility in Marica (Bulgaria). We thank Siemens Mobility for the trust they have placed in us and the excellent cooperation in achieving this milestone together."

Cost-effective refrigerant with a low environmental footprint

Liebherr’s HVAC units for the Railjet trains run with CO2, that is R744, which has a very low global warming potential and is therefore a climate-friendly alternative compared to other common refrigerants. It complies with current environmental regulations and is therefore also considered a future-proof solution. It is particularly energy-efficient and enables efficient heat recovery, especially when the systems are running in colder regions or under conditions of high temperature differences. Furthermore, the refrigerant is non-toxic and also non-flammable. As carbon dioxide is naturally available in large quantities, it is also a cost-effective refrigerant compared to synthetic refrigerants.