User-centric electrical vehicle thermal conditioning strategy based on close comfort elements in cold environment: Thermal manikin and human participants assessment

Heating, ventilation, and air conditioning (HVAC) system limit electrical vehicles (EVs) range as it induces important power consumption particularly in cold climate condition. In the present pilot study, the hypotheses are that EVs range could be improved by reducing HVAC setpoint consign and that despite the resulting lower cabin temperature, the thermal comfort could be at least maintained by proper activation of the heating elements near the occupant. Furthermore, one supplemental expectation is that associated thermal comfort and thermal sensation should be correlated between human participants' perception and thermal manikin's prediction. The objective of the present pilot study, involving a panel of six participants and the use of a thermal manikin, is to assess the comfort and energy efficiency of a strategy consisting in reducing the HVAC setpoint and compensating the ambient temperature reduction through heating seat (HS) and heating steering-wheel (HSW) activation. An EV exposed to an external temperature of -7 °C and two vehicle thermal conditioning strategies were compared: the configuration A consisted in activating only the HVAC in auto mode with setpoint 21; whereas in the configuration B, the HVAC was set in auto mode with setpoint 19 and HS and HSW were also activated. For both configurations, ambient temperature and EV power consumption was measured. Moreover, thermal sensation and comfort were assessed through human participants subjective evaluation and thermal manikin estimation. After 1 h, the energy consumption is reduced in configuration B compared to configuration A by 16,9 ± 1,5 %. Despite a lower temperature in configuration B, the global thermal perception perceived by participants and manikin is not impaired. The configuration B must be considered as a suitable strategy to reduce total energy consumption of EV maintaining users' thermal comfort. Overall, thermal manikin estimation correlated well with participants subjective thermal perception.