Studies have found that fuel use for air conditioning is between 5 and 15% of the annual fuel use for a standard car, while one study carried by the German Automobile Club ADAC demonstrates that for some popular European vehicles, air conditioning use when temperatures are above 22°C can generate up to 20% additional fuel consumption. Consequently, MAC systems used in vehicles are a significant source of greenhouse gas (GHG) emissions.
Glass for Europe recently released a position statement supporting the European Commission’s approach to look for all possible means to minimise the environmental footprint of cars. It estimates that high-performance glazing technologies, in particular solar control glazing, which is already available today, can reduce heat penetration in vehicles by over 25% and inside cabin temperatures by 7 or 8°C, thereby reducing the need to use air conditioning or its load and subsequently offering an “effective way to decrease carbon dioxide emissions generated from MAC systems”.
In Glass for Europe’s view, the Mobile Air Conditioning Initiative “should already serve to promote energy-saving solutions such as solar control glass in vehicles”, although it highlights that emissions from vehicle air conditioning are not yet accounted in official fuel consumption data and in the NDEC driving cycle, but “should be in the future to create a natural incentive for improvements”. It also calls for the role of glazing in reducing needs for air conditioning to be accounted for in test procedures to further boost the uptake of energy-saving glazing.
The work initiated by the European Commission on mobile air conditioning looks at ways to activate market mechanisms in a gradual way. It will serve in the first years to establish clear test procedures to quantify fuel efficiency of mobile air conditioning systems and to oblige car manufacturers to publish the fuel consumption of MAC equipment. Targets of MAC-specific emissions would be established for manufacturers to achieve by a certain date to provide impetus for further green technology development.
As a result of this work, fuel consumption generated by MAC could at last be taken into account in the overall fuel efficiency of vehicles. This would allow benchmarking overall vehicle efficiency against the EU target of an average 120g carbon dioxide/km for new cars in 2012.
Solar control glazing
Solar control glazing is a range of advanced glass products that provide not only good visibility and durability but also attenuate solar heat gain. Glazing with advanced solar control properties substantially reduces heat build-up inside vehicles and therefore either reduces the need to air-condition the vehicle or helps considerably lower the load on the unit.
Although solar control technologies are readily available to automotive manufacturers, most new cars are not yet equipped with these glass products to the detriment of passenger comfort and reduced carbon emissions. The main reason for this is simple: today, air conditioning use and related fuel consumption and carbon dioxide output, are not taken into account in vehicle’s official fuel consumption data. There is consequently no incentive for manufacturers to equip vehicles with solar control glass.
Encouraging automakers
“We believe that policy-makers should commit to concrete actions in the framework of an upcoming legislation on MAC efficiency,” says Glass for Europe, calling specifically for an ambitious carbon emission-reduction target for MAC systems, a test procedure to calculate carbon emissions due to MAC systems, consideration of glazing technology, surface area and inclination angle when assessing MAC performance, and the adoption of a technology-neutral scale to quantify benefits of solar control glazing.
“Through the MAC initiative, market mechanisms can be activated to encourage the use of solar control glazing in light-duty vehicles. It is policy makers’ responsibility to make sure that the appropriate test procedures and targets are put in place so that automotive manufacturers are incentivised to equip their vehicles with these energy-efficient glazing solutions,” says the Association.
Glass for Europe has four members: AGC Glass Europe, NSG Group, Saint-Gobain Glass/Sekurit and Sisecam/Trakya Cam and works in association with Guardian. Altogether, these five companies represent 90% of Europe’s flat glass production and supply nearly all the advanced technology glazing used by all European-based automotive manufacturers.
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