Modeling and simulation of thermal management in battery electric rail vehicles for the sizing of thermal storage systems

Abstract

The need for sustainable public passenger transport has led to an increase in the number of battery electric rail vehicles in development and operation. Nevertheless, the energy demand for the heating of the passenger cabin is provided by the battery and leads to limited range, especially at low ambient temperatures. Thermal storage systems offer an innovative possibility to reduce energy demand for heating from the battery. Therefore, the presented paper studies the requirements for such thermal storage systems in battery electric rail vehicles. A thermal car body model is developed in Python and the thermal energy demand in battery electric vehicle operation is simulated. Scenarios and boundary conditions for environment, track, vehicle and HVAC (heating, ventilation, air conditioning) control parameters are specified based on current codes and standards for rail vehicles. The thermal power demand is up to 48 kW in summer and 92 kW in winter for the presented scenario in climate zone III according to DIN EN 14750. The required size of a thermal storage system is between 52 kWh and 255 kWh. Overall, the application of these systems leads to an increased rail vehicle range of up to 5.6 %, which also leads to greater flexibility of the vehicles as they are more resilient against disturbances in daily operation.