J. Deur, I. Cvok, I. Ratković, J. Topić, J. Soldo, F. Maletić

Backward-looking Modelling of a Fully Electric City Bus with Emphasis on Cabin Heating and Cooling Subsystem

18th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES), Dubrovnik, Croatia, 2023.
Electrification of city bus transport represents an important step towards sustainable mobility. To facilitate electrification planning, a model of fully electric city bus (e-bus) is required, which predicts battery energy consumption for a given driving cycle. To this end, the paper proposes an e-bus backward-looking model describing the vehicle powertrain and longitudinal dynamics behaviour. The emphasis is on modelling of the heating, ventilation and air conditioning (HVAC) system through a regression model having four inputs: ambient temperature, solar irradiation, vehicle velocity and number of passengers (ridership). The HVAC system regression mode is parameterised to match the response of a first-principle Dymola model developed, and fine-tuned based on the experimental time response of city bus battery energy consumption. In order to gain insight into e-bus energy consumption variation with respect to operating conditions, a sensitivity analysis of the battery state-of-charge (SoC) trajectory is conducted with respect to different levels of A/C and ridership loads. Also, the e-bus model is simulated over each individual trip along the day to analyse variations in e-bus specific electricity consumption for real (recorded) city bus driving cycles.