Cabin comfort in business jets - development of model-based comfort and certification approaches

The aim of the “Novel Certification” project is to map the physiological response of humans in their thermal environment with the aid of simulations. To achieve this, a simulation model for the indoor climate, a zonal model, is coupled with a model which simulates the human response to the climate. The resulting thermo-physiological model can then be used to predict whether the person is still in their comfort zone or in danger of getting too hot or too cold. This is where the DressMAN comfort measurement system comes into play. The system makes it possible to validate the exchange of energy from a person’s body with their environment.

Thus, simulation can now be used as a tool in comfort studies to find out the most efficient measures to improve comfort. For extreme thermal cases such as extreme heat or cold, a thermo-physiological model can additionally be used to predict how the core body temperature will gradually adjust. As a result, limits can be defined of what is “tolerable” if the air-conditioning system fails.

The measurements are also used to evaluate local thermal comfort in the aircraft cabin and derive improvement measures.

The “Novel Certification” project was able to answer numerous questions on cabin comfort in business jets. For example, it was possible to demonstrate that although solar radiation through the window can warm parts of a person’s upper body, the effect is too small to cause discomfort of the whole body. Another example is the thermal bridge at floor level in an aircraft, which may cause cold feet. Heating the sidewall of the aircraft proved to be the most efficient measure against this because heat radiation enables warmth to reach the feet and lower legs.

The simulation model is currently undergoing validation and has already been coupled with a thermo-physiological model for the first time.

• Dassault Aviation