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J. Winzen, C. Marggraf-Micheel, H. Soll
Displacement ventilation (DV) is an air distribution system, which supplies cool fresh air at floor level and extracts exhausted air at the ceiling. Air draught is reduced as heat sources - like aircraft passengers - generate the vertical air movement in the room. Of current interest is the question whether ordinary mixed air systems in an aircraft can be replaced by or combined with displacement ventilation systems without risking a decrease in thermal comfort. A reduction of energy consumption seems to be a valuable gain. Three different versions of displacement ventilation were analysed in the research project "Innovative Cabin Systems"(1). For this purpose, new air outlets were installed in an aircraft mock-up of a Dornier 728. Outlets were integrated into the existing air conditioning system and fixed under the passenger seats. They were suitable to supply a sufficient amount of cool air with low speed to the cabin. Studies were conducted in the mock-up using 40 subjects each. They were aimed at analysing the thermal comfort of a) Study 1: 100% displacement ventilation, b) Study 2: a 70:30% hybrid solution combining DV and mixed ventilation (MV) and c) Study 3: a 50:50 % hybrid solution of DV and MV. Two climate scenarios corresponding to cruise flight conditions (23 °C and 24 °C) were tested. Objective and subjective data were gathered to gain a differentiated image of the climate situation. Various sensors were used to quantify the intensity of air velocity and temperature next to the subjects? bodies. Further, psychological questionnaires were filled out by the subjects, by which they evaluated intensity and comfort of the climate parameters. Measurement data revealed a comparatively strong vertical temperature gradient for hybrid systems; the smallest temperature difference between feet and head was found for 100% DV. Air velocity was altogether low and increased with the amount of mixed air that was provided. Regarding subjective evaluations, temperature, air movement and humidity were rated as being most comfortable in 100 % DV and in the 50:50 hybrid system. The overall satisfaction with the climate was highest in the 50:50 hybrid system. In sum, displacement ventilation can be used to provide a comfortable climate in an aircraft cabin. Even though known constraints as e.g. large vertical temperature differences are measurable, these did not have any negative influence on climate satisfaction ratings.
Deutscher Luft- und Raumfahrtkongress 2013, Stuttgart
Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn, 2013
21,0 x 29,7 cm, 9 Seiten
Stichworte zum Inhalt:
displacement ventilation, thermal comfort