CO₂ in bus mobile air-conditioning more efficient

The German environmental group DUH and the German automobile club VCD underline in a recent press release the advantages of CO₂ mobile air-conditioning (MAC) systems. Life cycle costs of CO₂ MAC would be considerably lower than for MAC using chemical refrigerants. The CO₂ MAC would work furthermore with higher efficiency and would allow savings of up to 70% in maintenance and servicing costs. These economic advantages are substantiated by clear safety and climate benefits where R744 could also be used in a heat pumping mode.

CO₂ MAC in buses

The call comes at a time when climate talks in Durban, South Africa, are looking for more sustainable technology solutions to the climate crisis mankind is facing. The public transport sector has a special role to play as all new coaches today are equipped with air-conditioning systems. 73% of buses that are during weekdays deployed in regional service and during weekends in interurban traffic, are equipped with air-conditioning. Also the percentage of air-conditioned urban buses is climbing. To name one example: in 2008, 64% of buses in Germany were equipped with air-conditioning systems, releasing in the same year almost 100 tonnes of their chemical refrigerant in the atmosphere. This is not unusual as bus air-conditioning systems on average leak 13.3-13.7% of their refrigerant yearly. The 100 tonnes of refrigerants vented into the atmosphere this way in 2008, were the equivalent to the CO₂ emissions of around 90.000 small cars in one year.

Seven public transport companies in Germany and Luxembourg have equipped a fleet of 22 buses with CO₂ air-conditioning systems so far. Experience shows that these climate friendly MAC use up to 25% less energy at the same capacity. This translates into considerable savings in operating costs for the transport companies.

European legislation

The recognition of R134a, the current refrigerant in mobile air-conditioning systems, as very climate damaging has led to a European directive, prescribing the use of refrigerants with a global warming potential (GWP) higher than 150 in the A/Cs of new types of cars from January 2011 on, and in all cars from 2017 on (so called MAC Directive, 2006/40/EC).

The DUH and the VCD would like to see this legislation extended. The director of the DUH Jürgen Resch pointed out that clear and timely legislation can speed up innovation. The MAC Directive should therefore include not only passenger cars and small commercial vehicles but all vehicles in general.

Informing consumers

In November 2010, the DUH and the VCD have started a large-scale information campaign called “Pro Climate: efficient car air-conditioning systems with natural refrigerants”. The campaign\'s objective is to inform consumers and car buyers about the climate impact of mobile air-conditioning based on the used refrigerant and the degree of system efficiency as well as the increase in fuel consumption related to the use of air-conditioning in cars. It will run for three years and is partially funded by the EU LIFE+ programme that supports projects in the field of environmental protection.

In February 2011, an online survey was started in order to raise awareness and give consumers valuable tips on the use of their car air-conditioning systems and related information on the new directive in exchange for answers to seven short questions. This survey is now also available in English.

Informing stakeholders

On 13 December 2011, Pro Climate furthermore brings together key stakeholders in the European mobile air-conditioning field to discuss the environmental impact of MAC systems as well as technical and political solutions. The event takes place in the Representation of the European Commission in Berlin, Germany.