Multi-jet personalized ventilation in passenger trains: Objective and subjective thermal comfort

• All 40 subjects chose different air velocity combinations of the six-nozzle-PECS. • Equivalent temperature variations up to 11 K were found for the subjects’ settings. • Lower flow rates were chosen for the head compared to the other body parts. • The nozzles increased subjective comfort evaluation in the train laboratory. • Individual airflow settings were more important than actually having control. Installing local, individually controllable ventilation – a specific version of a personalized environmental control system – offers great potential in terms of improving the individual thermal comfort and energy savings of the overall train air-conditioning system. In our experimental investigation, we set an increased mean temperature in the train compartment and measured the local equivalent temperature (T eq ) and local mean vote (LMV) per body-segment on a selected seat. This seat was equipped with an additional six-air-nozzle device attached to the backrest of the front seat. The objective comfort revealed the achievable ranges for the different settings as well as a strong local effect of the single air jets. The different configurations were afterwards studied in terms of subjective comfort evaluations based on questionnaires and the individual settings of 40 subjects. The results confirmed the positive cooling effect of the air jets as thermal comfort was significantly improved when the subjects used the six-air-nozzle. Air draughts at the subjects’ upper legs and the temperature at their chest and face were most relevant for comfort sensations. Furthermore, the findings highlighted the highly subjective demand on the thermal environment as no two subjects chose the same nozzle configuration.