The German Environmental Aid Association (DUH) is calling for a swift switch to environmentally friendly CO2 mobile air conditioning (MAC) systems for buses. The association notes that bus manufacturers will play a vital role in this transition, as transport companies are already showing great interest. 

Hessen sets an example 

Hessen RhönEnergie Bus GmbH has proven itself to be a leader in the field of CO2 MAC, adding twelve more buses using CO2 refrigerant to its fleet in Bad Hersfeld. These will be in addition to the company’s six buses using CO2 in the town of Fulda, deployed two years ago. CO2 is a natural and sustainable alternative to current refrigerant R134a, which contributes to global warming, and is already banned in new passenger vehicles models. DUH national manager Jürgen Resch commended RhönEnergie Bus GmbH on taking the initiative to employ the sustainable and climate-friendly technology, and urges other transport operators to follow Hessen’s example. He noted, though, that the responsibility falls not only on transport operators, but also on bus manufactures. Resch sees manufactures MAN and EvoBus as having a vital role in the transition to CO2 MAC. 

The polls are in: CO2 is the future 

CO2 MAC systems are in demand according to results from DUH surveys. Conducted among transport companies in Germany, Austria and Switzerland between 2011 and 2014, the surveys concluded that nearly 50 companies would like to use CO2 air conditioning technology in the future. Combined, this would amount to a fleet of more than 3,200 air-conditioned vehicles. Although some of the companies surveyed expressed reservations about the technology, transport expert Axel Friedrich believes it will not take long before such doubts are allayed: “When bus manufacturers finally commit to the optimisation of the components and provide appropriate equipment from the factory, the last critical voices will too be convinced of the benefits of CO2 cooling.” 

Lower costs combined with low environmental impact 

Aside from the low environmental impact, the low maintenance costs and the ability to use CO2 systems in conjunction with a heat pump for efficient heating in winter are further advantages to CO2 MAC technology. CEO of RhönEnergie Bus Thomas Lang stated, “The buses run flawlessly – and especially with the temperatures recently, we were able to stress-test our air conditioning systems, and they passed with flying colours.” 


The DUH, with funding from the German Federal Environmental Foundation (DBU) continues to support the use of natural refrigerant CO2 as an alternative refrigerant to R134a. 



Press release – DUH calls for CO2 MAC technology in buses (in German)

Author Elke Milner