Mixing ventilation by in-seat air outlets for single-aisle aircraft

Abstract In recent years, alternative ventilation systems for aircraft cabins have attracted the attention of scientists and aircraft manufacturers due to their potential to save energy and increase thermal comfort. The aim of this study was to investigate whether comfortable thermal conditions for the passengers can be achieved by a floor-based cabin displacement ventilation (CDV) in combination with an in-seat ventilation (ISV). The two alternative ventilation systems were therefore investigated in the Dornier 728 test facility of the German Aerospace Center in Göttingen. Firstly, ISV, where fresh air flows vertically into the cabin in the immediate vicinity of the passengers through air outlets attached to the back of the seats, and secondly, CDV, which is based on low supply air velocities through dense membranes under the seats. Furthermore, the potential of combining the two ventilation technologies to create a hybrid ventilation system in the single-aisle cabin was investigated. The measurement techniques were selected and designed to quantify and evaluate the following parameters: boundary conditions, cabin air temperature, efficiency of the ventilation concept, flow velocities, 3D flow measurements and thermal comfort. The results showed that neither CDV nor ISV alone meets the comfort requirements. However, combining the ventilation systems produced good results for the ventilation of a single-aisle aircraft. Despite the high inflow velocities associated with ISV, no threshold values were exceeded near the passengers. Furthermore, ISV reduced the uncomfortable temperature stratification in CDV. Combining the systems resulted in equivalent temperatures that were neither too warm nor too cold for all body parts.