Experimental evaluation of alternative ceiling-based ventilation systems for long-range passenger aircraft

Abstract

Alternative ventilation technology bricks, such as ceiling-based, sidewall-based or floor-based ventilation, are of high interest in terms of manufacturing and customization benefits for passenger aircraft. Two novel ventilation systems and state-of-the-art Mixing Ventilation (MV) were experimentally investigated under static conditions in a ground-based research facility. In case of Micro-Jet Ventilation, a perforated ceiling brings the air into the cabin as localized micro-jets with high momentum. Further, Low-Momentum Ceiling Ventilation characterized by a low-momentum air supply through planar and large-surface inlets is investigated. The measurement techniques and the test matrix were designed in order to quantify and evaluate thermal comfort, local air quality and energy efficiency of the ventilation concept. The results proved that there is not one single ventilation concept which optimizes all challenges: air quality, thermal comfort and energy efficiency. Both advantages and disadvantages were found for each ventilation system. In terms of technology bricks, the following main results were found: The average local age-of-air was between 5 and 14%, depending on the boundary conditions. It was lower for the ceiling-based concepts compared to state-of-the-art MV. At the same time the average CO2 concentration decreased by 7–14% for the ceiling-based concepts compared to MV. The local velocities in the vicinity of the passengers were similar for cruise conditions, whereas they decreased by up to 38% in case of hot-day-on-ground conditions for ceiling-based ventilation compared to MV. On the other hand, the heat removal efficiency was low for all concepts and the temperature stratification increased in case of ceiling-based ventilation.