Autoklima Optimierung mittels SLS

In Europe, passenger cars are responsible for 12% of CO2 emissions. The European Commission established new targets to drastically reduce the emissions on a fleet level of 35 g CO2 per km until 2021. The presented industry-driven project aims to reduce energy consumption by up to 35% of air-conditioning (AC) in passenger cars with the introduction of a novel system. The developed solution reduces the fuel consumption of AC to up to 50% for gasoline engines. This success was achieved by implementing a new AC-concept consisting of three strategic measures: Recycling of cool air from passenger cabin to lower the temperature of incoming air Implementation of a patented dual box recuperation air preconditioning system Design and material optimization of the box’s walls acting as heat exchanger for improved energy transfer By means of Selective Laser Sintering (SLS) design freedom and short production cycles of test parts, the design of the AC box was considerably optimized to increase its contact area between recycled and incoming air. To further increase the heat exchange throughout the system, the thermal conductivity of SLS material was improved by incorporation of mineral fillers. The successful implementation of both optimizations led to a CO2 emission reduction of around 50% for the climate control of passenger cars. This could be measured explicitly in climate chamber testing of the new system implemented in a real car (Mercedes C-Class). Furthermore, as a non-expected very surprising effect in the project, it could be revealed that the pronounced roughness of the parts produced with SLS supports the heat transfer by micro-turbulences and improves the desired energy transfer effect. This means that SLS parts due to their surface roughness are more suitable for this purpose than parts made by injection moulding.