Evaluation of novel ventilation concepts for train compartments using thermal manikins and subject trials

Kurzfassung

In the framework of the Next Generation Train (NGT) project of the German Aerospace Center (DLR), different aspects of future high-speed trains and the intermodal passenger and freight transport are addressed. Among many others, the thermal passenger comfort and the energy efficiency of the ventilation system are tackled. Aim of the present study is to identify novel ventilation concepts, which yield a higher comfort level, less energy demand and help to avoid the spreading of infectious diseases. Therefore, studies using thermal manikins and subject trails were performed in a generic train compartment representing the lower level of the NGT high speed train. Besides classical “micro-jet” ventilation, three novel ventilation concepts, comprising cabin displacement ventilation, ceiling based low momentum ventilation as well as hat-rack integrated low momentum ventilation, are investigated. First results covering mean flow velocities and temperatures in the seating zone as well as the heat removal efficiency are presented. These reveal, that displacement ventilation promises high potential for energy saving in combination with very low flow velocities, however, the temperature gradient between head and ankle is increased by a factor of four as compared to the other concepts. Furthermore, subject trails and objective measurements reveal, that hat-rack integrated low momentum ventilation, which is highly capable of being integrated in the structure, performs comparable or better compared to classical micro-jet ventilation. At the conference, we will present a detailed analysis of main flow features and other comfort relevant quantities for all different ventilation concepts. Furthermore, a comparison of the different ventilation concepts revealing the specific advantages and potential disadvantages in detail will be given. It comprises results of subject trails performed at different temperatures of the inflowing air as well as thermal manikin studies.