With vehicle electrification, the competition to design and manufacture the most efficient powertrain possible is stronger than ever - with many hurdles to overcome. One of them is the strong influence of the thermal behavior on the energy characteristics. At the same time, the complexity of vehicle thermal management systems is increasing, making the integration of these systems into the vehicle even more challenging. System simulation is an extremely efficient way to support this process all the way from the concept to the integration phase of development.