Economic Assessment of Different Air-conditioning and Heating Systems for Electric City Buses Based on Comprehensive Energetic Simulations

Abstract

The air-conditioning and heating of the passenger cabin in an electric bus leads to a significant increase of the auxiliaries' energy consumption. Due to limited battery capacity, the daily operating range of electric buses depends considerably on the ambient climate. In particular, heating is an energy-intensive process since no waste heat from the IC engine is available. Energetic simulations show drastic range reductions when the interior is heated by an electric resistance heater. In contrast, the range reduction can be limited noticeably if a heat pump is utilised. Therefore, the selection of heating and air-conditioning (HVAC) systems has a significant impact not only on the range but also on the operating costs of an electric vehicle.The aim of this study is to conduct a cost analysis for different HVAC systems of an electric city bus. The economic assessment is based on comprehensive energy consumption simulation and a life-cycle costing approach considering all expenses of the operation period.The examination reveals that the heat pump systems feature significant energy savings compared to conventional HVAC systems. However, over a life span of twelve years, the current high acquisition cost of a heat pump system is not compensated when only considering direct cost.

System Perspective on Biogas Use for Transport and Electricity Production

“…Heating was assumed to be generated by an onboard heat-pump with COP 3.0. This assumption is in accordance with Göhlich et al [24].…”

“…Heating was assumed to be generated by an onboard heat-pump with COP 3.0. This assumption is in accordance with Göhlich et al [24]. Heat load in the model, presented with monthly duration diagram, i.e., days sorted by heat load in each month.…”

Design of urban electric bus systems

“…In the case of resistance and diesel heaters, constant efficiencies from manufacturer datasheets are assumed; for heat pumps and refrigeration units, a variable efficiency is calculated from a refrigerant circuit model parameterised using manufacturers' data. The passenger cabin model includes convective and radiation heat exchange with the environment, inner thermal loads and air exchange through open doors (Göhlich et al 2015;Jefferies et al 2015).…”

“…The passenger cabin model includes convective and radiation heat exchange with the environment, inner thermal loads and air exchange through open doors (Göhlich et al. 2015; Jefferies et al. 2015).…”

Electrification of a City Bus Network: An Optimization Model for Cost-Effective Placing of Charging Infrastructure and Battery Sizing of Fast Charging Electric Bus Systems

“…It is assumed that the required energy of heating, ventilation and air-conditioning (HVAC) and other devices is provided by the battery. The values presented in Table 2 are simulated for different ambient temperatures scenarios using an electric positive temperature coefficient (PTC) heating and a roof top air-conditioner with electric compressor according to methodology of [39][40]. Referring to these studies, the set temperature for the passenger cabin is 20°C for heating mode and 25°C for cooling mode.…”