E3S Web Conf.
Volume 111, 2019CLIMA 2019 Congress
|Number of page(s)||8|
|Section||Advanced HVAC&R&S Technology|
|Published online||13 August 2019|
Analysis of Defogging Performance, Thermal Comfort, and Energy Saving for HVAC System Optimization in Passenger Vehicles
1 Tokyo City University, Graduate School of Integrative Science and Engineering, 1-28-1, Tamadutsumi, Setagaya, Tokyo, Japan
2 The University of Tokyo, the Institute of Industrial Science, 4-6-1, Komaba, Meguro, Tokyo, Japan
* Corresponding author: email@example.com
The heating, ventilation, and air-conditioning (HVAC) system in a vehicle is used for both defogging the windshield and ensuring the thermal comfort of passengers. A challenge is that energy savings in the HVAC system lead to decreased system performance. The three objective functions, i.e. defogging performance, thermal comfort, and energy savings, these must be considered in parallel to find the optimized control strategy. In the present study, a transient numerical simulation of the in-vehicle environment is performed and the dependency of performance on the air flow rate and supplied air temperature is analyzed. The criteria of defogging performance and thermal comfort are determined as the constrained conditions. The results show a trade-off relationship between the air flow rate and air temperature in defogging performance and thermal comfort; however, their sensitivities depend on the conditions and the time elapsed. As for transient defogging performance, the air flow rate has greater impact than airflow temperature. The air flow rate and the air temperature are comparable in their effects on equivalent temperature, which is employed as the index of the thermal environment. The blowing condition range that fulfills the criteria makes a transition to a low-energy condition with time elapsed. A control strategy for the air flow rate and temperature is derived considering the transient and steady-state conditions.
© The Authors, published by EDP Sciences, 2019
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