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Thermal Comfort Modeling of Cooled Automotive Seats
Abstract:
Seat cooling systems are becoming more common as luxury features offered by original equipment manufacturers. Despite the extensive research & application of these systems, a thermal model and comfort requirements of the occupant/seat system have not been established. Without a model or thermal criteria for comfort, the seat temperature & humidity conditions required for optimal comfort can not be defined.
A synopsis of the thermal comfort conditions required to achieve an occupant's subjective comfort as well as their comfort transition points are explained. In this context a model is designed specifically from a heat and mass transfer perspective between an occupant and a seat cooling system. Focus is given to the local conduction, convection, and evaporative cooling that takes place at the body to seat surface interface. The goal of this model is to examine the occupant's physiological response to the seat cooling system in order to identify what thermal conditions & energy quantities are required to achieve an occupant's local neutrality point. The model is then verified using a pre-defined 50th Percentile American Male (AM50).
With a defined AM50 occupant under varying thermal conditions the quantities of energy transfer required to achieve thermal equilibrium (comfort) have been defined. In conjunction the ratios of the necessary heat transfer to mass transfer (moisture removal) were defined in order to give total comfort to an occupant at the same conditions.
The benefits from the investigation findings will allow for seat cooling system designs to be optimized or improved for next generation seat cooling systems. Using this component level model in conjunction with the total HVAC system would allow for future studies in regards to a total occupant comfort system with reduced power consumption & maximized occupant comfort.