Numerical Simulation of Thermal Comfort in Passenger Car Compartment Using CFD-Heat Transfer Coupling

Abstract

While heating, ventilation, and air conditioning (HVAC) systems provide thermal comfort for the car occupants, the passenger compartment’s thermal environment is not uniform and needs to be further assessed. Different cars have different car compartment designs too, thus, the distribution of the airflow and temperature field inside the passenger compartment has to be examined so that improvements in the different car designs can be proposed. Hence, this study aims to investigate the thermal comfort in a Malaysian local brand sedan car which is Proton Saga FLX 2012 using the coupling of computational fluid dynamics (CFD) and heat transfer. A simplified human model was included in the car to allow the understanding of the effect of airflow and temperature field distribution on the passengers sitting under ventilation system conditions. A few conditions also were simulated; without outlets where all windows close (Case 1) and with different window openings (Case 2). The thermal comfort of the passengers was analysed based on the temperature or thermal field displayed on the human models. The head, hand, torso, feet and overall temperature were evaluated. The results showed that in the no outlet condition when all windows were closed, air conditions were on and the initial compartment temperature was at 50°C, it can cause hyperthermia stage to humans. Besides, the hands will have the lowest body temperature in both situations with and without window openings because it is directly facing the air-conditioning. In addition, window opens have pleasant air velocity compared to those without windows open.