Evaluation of dehumidification capacity and operation boundary constraints for different thermal management systems for electric vehicles

The thermal management systems of electric vehicles (Evs) are promisingly developed for better comfort and efficiency, resulting in various dehumidification and reheating architectures. Due to the energy distributions and coupled effect, the dehumidification capabilities and operation boundaries are often limited in extreme conditions for different systems, compromising driving safety. To address this issue, an experimental system was constructed, and a mathematical model was developed and validated to analyze the performance of four dehumidification systems: the parallel dual-gascooler system, the parallel dual-evaporator system, the partial series system, and the whole series system. The dehumidification capacity of the four systems was evaluated under varying indoor air mass flow rate, with a focus on identifying the reasons for the dehumidification limitations observed in the whole series system. Additionally, the effects of key parameters, including discharge pressure, ambient temperature and humidity, evaporation temperature, and supply air temperature, on the dehumidification capacity were examined under maximum air mass flow rate conditions. The DHCOP of the DES was the highest, surpassing that of the DGS by 107.6 %, and the MER of the DGS was the largest, exceeding that of the DES by 5.9 %. Furthermore, the extreme intake air temperature and humidity conditions under which these dehumidification systems can effectively achieve both dehumidification and supply air temperature requirements were identified, and the variation law of the operable boundaries for these dehumidification systems across a wide range of environmental parameters (temperature: 10–24 °C, humidity: 60–100 %) was determined. This study provides a valuable reference for the selection and performance difference analysis of dehumidification systems in practical applications.