How can a vehicle be climate-friendly efficiently? Researchers at the Technical University of Munich (TUM) pursued this question in the context of the Visio research programme.M funded by the German Federal Ministry of Education and Research (BMBF), with a total of €7.1 million.
The results of their research show that the potential of energy efficient in air conditioning is almost exhausted. And this applies equally to gasoline cars. Inefficiency has its advantages: in the past, waste heat from combustion engines could be used to directly heat the interior of the vehicle. But efficient electric motors generate almost no waste heat. The question of climate control of electric vehicles therefore needs to be resolved again.
The researchers quickly determined that cooling in direct proximity to the body is always the most efficient alternative. Unlike previously deployed solutions, in which the entire interior is cooled or heated to the same temperature, heat is generated or dissipated only where it can really be felt by passengers.
"Our tests showed that uniform climate control is not necessary," says Marius Janta, professor of ergonomics at TUM. "When we warm up a passenger's seat on cold days, they find it pleasant. That is, with just a small amount of energy, you can significantly reduce the feeling of discomfort."
The temperature control of the seats was carried out using Peltier elements, thermoelectric semiconductors that can be used for both heating and cooling. "Even though Peltier elements are relatively expensive, they heat or cool immediately," says Alexander Präbst, also from TUM. "Compared to cold starting a combustion engine in winter, we even managed to improve the comfort level." In addition, on very cold days, a supplemental bioethanol heater can be turned on without sacrificing efficiency.
This thermal management system is controlled by intelligent and self-adaptive software, based on an evolutionary algorithm that is developed at the university. The system evaluates the signals from the temperature and humidity sensors and automatically regulates the optimal settings for comfort, safety and efficiency using a computer model.
They have also improved driver comfort much more due to an application that, from a smartphone, allows you to plug in the heating or air conditioning before reaching the vehicle. Since it is programmed with open source software, extensions to this application could be enabled in the future without having to go through the workshop.
