Dynamic cabin model of an urban bus in real driving conditions

The transport sector is a key sector to reduce the emission reduction targets. The main auxiliary load, the HVAC system, contributes significantly to the energy consumption and affects the driving range in electric vehicles. Accurate and dynamic models are needed to optimize these systems in urban environments. This research presents a dynamic thermal model of a cabin, including a detailed 3D urban model, a consistent weighted stochastic kinematic model, a climate model accounting for all bus surfaces and environment, and a transient thermal model of the cabin. A validation was performed against dynamic experimental tests. The most demanding mode is for cooling, with a mean cooling demand of 105 kWh/100 km in a warm summer day. The heating demand on a cold winter day is around 22 kWh/100 km. The components analysis reveals that the occupancy contributes to 33-45 % of the cooling demand in summer and the solar components account for 20-42 %. Air changes contribute to 20 % of the heating demand in winter, and conduction, convection, and internal infrared components represent 40 % of the negative load, except for summer when they account for 10-20 % of the positive load. A sensitivity analysis has also been performed to quantify the impact of different strategies.