Development and Validation of Feet Thermal Comfort in Very Cold Climate with high fidelity to capture a transient heat transfer phenomenon

Customer Centric approach drives the automotive industry to focus on providing adequate cabin thermal comfort in cold & very cold environments. The quotidian life of a driver from countries in the northern hemisphere faces the issue of cabin temperatures plummeting below 0 deg C in winter. This permeates the passengers and leads to serious conditions like frostbite and hypothermia with prolonged exposure. Transient Validation of Thermal Comfort for 'Customer-centric Heating cycles' replicating regular commute (1 hour) from Home-to-Office is set as target for transient method development in FLUENT & CCM+. This precludes the requirement of comfort achievement with transient targets with high fidelity in HVAC, Stratification of flow through ducts, Material strategies in cabin, positioning of vents, optimum distance between vent to head/feet and furthermore. This paper explicates the thermal and flow behavior of Hot air from lower ducts toward front driver and front-rear passengers and evaluate the comfort level based on effective heating coverage of FEET. Furthermore, we determine the dead zones, analyze the cold bubble movement, recirculation strategy considering energy optimization of compressor. Also, we correlate the temperatures sensors near the mannequin using the Average Root Mean Square Error (RMSE) for 8 feet probes and 4 head probes (RMSE: 1.9°C & 2.7°C) between physical test and Simulation for more digital reliance and quick decision making. We put forward a detailed DOE for analyzing the Energy imbalance (to be <1%) within cabin as a system to evaluate the re-circulation strategy [Blown Air = Fresh Air + Re-Circulated Air from Cabin]. We achieved an accuracy of 95% correlation for ICE-hatchback, EV-hatchback and EV-LCV and relay on simulations for vehicle development.