As the global automotive industry makes a critical transition from the traditional ICEVs (Internal Combustion Engine Vehicles) to EVs (Electric Vehicles), it faces two conflicting technological challenges: 1) range degradation in cold weather conditions and 2) reducing time to thermal comfort in winter driving in absence of waste heat from the IC engine. Next to the EV drivetrain, the HVAC (Heating Ventilation and Air Conditioning) system is the highest consumer of electric power in the vehicle. To get the occupants to a thermally comfortable state as quickly and efficiently as possible, automotive OEMs (Original Equipment Manufacturers) are exploring microclimate systems that involve localized heating and cooling. Unlike the central HVAC system, localized heating and cooling devices such as climate-controlled seats, steering wheel heaters, neck warmers, etc. directly condition the occupant rather than conditioning the entire cabin environment to provide thermal comfort to the occupant. Consequently, microclimate systems improve time-to-comfort while being energy efficient. In this paper, a general methodology to design a human-centric auto-climate control system is presented. Such a system uses microclimate devices in conjunction with the electric HVAC or heat pump system and the control is based on real-time estimation of heat transfer rates to the occupant. This approach can provide additional benefits such as enhanced personalization along with energy savings and reduced time to comfort. The authors have also highlighted the challenges associated with existing measurement and data acquisition systems including calibration, verification and validation and have recommended a real-time comfort metric measurement system as a possible solution for future development.
