Efficient Air Conditioning of Battery-Electric Multiple Units (BEMU): Modeling and Optimization

Abstract

The power required for heating, ventilation and air-conditioning (HVAC) of the passenger compartment in BEMU strongly affects the capacity and lifetime of the battery. Accordingly, 11 different measures for reducing the energy demand of HVAC are presented in this paper. The measures are investigated using Dymola models of a thermal car body to determine the energy saving potential as well as the effects on the vehicle. Reducing the amount of fresh air while complying with CO2 limits and using a heat pump are efficient measures to reduce the annual energy demand for the HVAC system by 62% or 48%, respectively. In addition, a control-based, catenary dependent HVAC operating strategy is being developed that decisively reduces the load on the battery during dynamic operation. This approach is particularly suitable for straightforward implementation since no design changes to the vehicle are necessary.