Advanced Temperature Control in Aircraft Cabins - A Digital Prototype

For thermal cabin control of commercial aircraft, the cabin is usually divided into a small number of temperature zones. Each zone features its own air supply pipe. The necessary installation space for ducting increases significantly with the number of zones. This requires the number of temperature zones to be low. Factors such as seating layout, galley placement and passenger density result in deviations in heat flux throughout the cabin. These deviations cannot be compensated by the control system, if they occur within the same temperature zone. This work presents a novel temperature regulation concept based on local mixing. In this concept, two main ducts span the complete cabin length, and provide moderately warm and cold air. At each temperature zone, cabin supply air is locally mixed using butterfly valves. In this way, the number of temperature zones can be individually scaled up without any additional ducting, only requiring additional valves for each temperature zone. The access to hot trim air at the site of the mixing chamber can therefore be omitted. The advantages of this concept are bought at the expense of a more complex control system and a more sophisticated management of failure modes. Pneumatic coupling between temperature zones is much more pronounced compared with the traditional architecture. A centralized control architecture is required. A prototype architecture is presented, as well as a corresponding control system candidate. Possible strategies for the handling of failure modes are discussed. High fidelity simulations using the object-oriented equation-based modelling language Modelica are used to demonstrate robust performance under a wide range of boundary conditions.