2017 ASHRAE Annual Conference

Passenger comfort and ventilation efficiency in cars have attracted the attention of scientists and car manufacturers during the last years due to their potential of improving thermal passenger comfort, increasing efficiency and attended energy reduction. Nowadays, state of the art for the ventilation of passenger compartments of cars is mixing ventilation (MV) which is based on a high mixing degree of inflowing air with cabin air. In cooling cases, this is realized by high-momentum jets of cold air, which enter the cabin at the dashboard. Among the potential benefits of new developed ventilation concepts, are an increased thermal passenger comfort by reducing draughts and simultaneously energy saving potential by increasing the heat removing efficiency (HRE). The latter is of great importance especially for electrically powered cars to improve their range.

Improving comfortable environmental conditions for passengers has been the airlines’ interests in the recent decades. This paper discusses air distribution systems and factors affecting the goal of a healthy and comfortable environment for the passengers and cabin crew. Research was done by using ANSYS FLUENT 17.0 with new features. The standard air distribution systems used in recent air cabin are combined between mixing ventilation and personalized ventilation and this study makes a simple applicable modification on the ventilation system that improves the ventilation efficiency, thus protecting the passengers from being infected by each other. Commercial airplane environmental control systems (ECS) currently mix air ventilation systems, which are necessary to make a safe, thermally comfortable and healthy cabin environment.

A number of studies have shown that air distribution systems on the thermal comfort of occupants can vary depending on locations of diffusers and return outlets and types of ventilation systems. However, few studies have focused on air distribution strategies for serving multiple zones and their effects on local air quality and thermal comfort. Simulation results indicate that temperature distributions of two rooms were a strong function of ventilation type. However, indoor air quality of two rooms was significantly affected by both a ventilation type and an operation strategy. The results suggest that careful consideration is needed for designers and managers in selecting and operating air conditioning system to maximize the ventilation effectiveness and the thermal comfort in multiple zones.

Air-conditioning systems are often designed based on the model experiment and the numerical simulation. However, such study methods spend much time and costs in order to obtain the result. Therefore, the prediction method of indoor thermal environment with less time and cost is required. As for the practical use period, the air-conditioning system controls the supply air temperature and the airflow rate based on the feed-back control system which has temperature sensors. In this paper, Contribution Ratio of Indoor Climate (CRI) is employed to predict the distribution of the air temperature for the sake of the more efficient control system. The vehicle cabin and its air-conditioning system are focused because in-vehicle environment is a relatively severe condition compared with indoor environment of building. The purpose of this paper is to investigate the prediction accuracy of the air temperature in vehicle with CRI in order to clarify its applicability.