Evaluation of different air distribution systems for sleeping spaces in transport vehicles

• Thermal comfort and air quality in a small sleeping space were studied.
• The study used a validated CFD tool.
• Various ventilation systems were considered.
• Personalized ventilation is better than the mixing or displacement ventilation.

Air distribution in the sleeping space of a transport vehicle is important for sleep quality, especially during a long journey. In order to design a thermally comfortable sleeping space with fresher air, this investigation used a verified computational fluid dynamics (CFD) method to obtain the distributions of air velocity, air temperature, and CO2 concentration in the sleeping space with displacement, personalized, and mixing ventilation systems. This study used the facial-area speed ratio, mean age of air, and draft risk obtained by CFD to evaluate the air distribution effectiveness. The results showed that the performance of the personalized ventilation system was better than that of the displacement and mixing ventilation systems because it provided superior thermal comfort and higher air quality. The distributions of air velocity, air temperature, and contaminant concentration computed by CFD were validated with corresponding experimental data obtained in a full-scale test rig.