Analysis of Energy Consumption for Heating City Electric Buses and Ways to Reduce It

For regions with cold climates, the driving range of electric buses becomes a significant obstacle to the broader adoption of this type of transport. The increased energy consumption affects not only the range of autonomous operation but also the lifespan of battery packs, the scheduling of bus departures, and the load on the charging infrastructure. In this context, finding ways to reduce the energy consumption of the climate control system is an actual issue. The aim of the presented research is to experimentally and computationally determine the energy consumption for heating the driver's cabin and passenger compartment of an electric bus during the autumn-winter operation period, as well as to identify and analyze ways to reduce this energy consumption. To determine the air temperature in the passenger compartment, a mathematical model based on heat balance equations was used. This model was validated using data from real-world tests. The research was conducted at a proving ground under two conditions: driving at a constant speed and simulating urban bus operation with stops and door openings. The article presents the results of tests aimed at determining microclimate parameters and energy consumption for heating under various driving conditions. The causes of heat loss in electric bus heating were analyzed. It was found that approximately 35% of heat is lost through the ventilation system operating in fresh air intake mode, around 30% is lost due to door openings at stops (in the SORT2 urban driving cycle), 17% dissipates through the windows, and 18% through the bus walls, floor, and roof. Using the mathematical model, a series of calculations were performed to estimate total energy consumption over the heating season for various heating systems. The results showed that a system with a thermal storage unit consumes a total amount of energy comparable to that of an electric heating system over the season but reduces the load on the traction battery from the climate control system by 2…3 times. On the other hand, a heat pump also significantly reduces the electrical load, but the characteristics of the refrigerant used in the pump must be considered, as they greatly affect the operating temperature range and pump efficiency. It was determined that by adjusting the operating mode of the air recirculation system, overall energy consumption can be reduced by 35…39%.