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

Abstract

Installing local, demand-controlled 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 (Teq) 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. Objective comfort revealed the achievable ranges for the different settings and strong effect of the local air jets. This configuration was afterwards studied in terms of subjective comfort evaluations based on questionnaires and individual settings of 40 subjects. The results confirmed the positive cooling effect of the air jets as thermal comfort was significantly improved when subjects used the six-air-nozzle. Air draught at the subjects’ thighs and the temperature at their upper body 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.