The effect of a dual condensing system on the driving range for battery electric vehicles

Abstract

The air-conditioning system of a battery electric vehicle (BEV) serves a dual purpose as a cabin space cooling and thermal management of the battery. However, this operation requires high electrical energy. Consequently, the efficiency of air-conditioning (AC) systems is a critical factor in the energy consumption of BEVs. This study conducted a comprehensive model-based analysis on both the cabin and AC systems to investigate the influence of the condenser design on the energy consumption of BEVs. The two different types of condensing system were considered, a full sized air-cooled condenser and dual condensers (a water-cooled condenser with a minimized air-cooled condenser). The performance of the BEV AC system was investigated under diverse external and driving conditions. We discovered that the AC system utilizing the dual condensers reduces the high-side pressure compared with the air-cooled condensing system alone. In addition, the coefficient of performance (COP) was improved from 2.7% to 9.6% depending on airflows passing through the cooling module, particularly under urban driving conditions (such as idling and low-speed driving). Furthermore, when comparing the power consumption of the AC system to the overall energy consumption required by the vehicle within the North American SC03 fuel economy and emission measurement driving mode, it was found that the compressor's power consumption in the dual condensing system was reduced by 13%, compared to the air-cooled condenser system. In addition, the power consumption of the cooling fan was decreased by 17%. In conclusion, the dual condensing system is an effective condensing methodology capable of enhancing the overall driving distance per unit energy (km/kWh) by up to 7.9%.

Keywords

• Electric vehicle
• Air-conditioning system
• Dual condensing
• Efficiency improvement
• Driving range