Design and experimental evaluation of multi-mode HVAC system with dehumidification heat pump capability for electric vehicles

This study proposes a multifunctional heating, ventilation, and air conditioning (HVAC) system for electric vehicles capable of performing dehumidification and heating simultaneously using only one compressor. The system operates in four modes: air conditioning, pure heat pump, pure dehumidification, and dehumidification-heat pump, depending on the environmental conditions. An experimental platform is constructed using automotive-grade HVAC components to evaluate the performance of the proposed system under controlled season-specific temperature and humidity conditions. The results showed that at an ambient dry bulb temperature of 35 °C, the air-conditioning mode reduced the temperature in the simulated compartment to 24.2 °C within 5 min. Moreover, under low-temperature conditions of 7 °C, the pure heat-pump mode increased the cabin temperature to 30 °C within the same time frame. In the combined dehumidification-heat-pump mode, the system achieved a COP of 3.32, which was higher than that of current EVs. Overall, the findings indicate that the proposed HVAC system meets the relevant CNS standards and provides a feasible solution for climate control in EVs, particularly in cold and humid conditions.