A zonal drying system developed by Sweden's CTT Systems is to be offered as a standard option on Boeing's Next Generation (NG) 737 family. It will be available from April following its selection by several European charter operators, including Air Berlin, Hapag-Lloyd and Sterling European Airlines.
The system eliminates condensation on the aircraft structure by drying the inter-costal area between the cabin ceiling and sidewall panelling and the inside of the aircraft skin. The drying unit is fitted in the upper crown secondary support structure in a widebody aircraft or below the floor in a narrowbody, and operates by sucking air via a filter through a rotor impregnated with silica gel.
Dry air is then blown via a piccolo tube between the cabin liner and the skin, drying the inside of the insulation blankets. These have been known to absorb up to 400kg (880lb) of water on large aircraft such as a Boeing 767, says CTT president Torbjorn Johansson.
About 20% of the air passing through the unit is warmed and regenerates the silica by reabsorbing some of the water, which is then returned to the cabin. The remaining water is ducted into the water storage and drainage system. The installation in a Boeing MD-80-size aircraft weighs 12kg, about 30kg in a 767 and almost 40kg in an MD-11.
CTT has also developed a humidifying "Zonal Comfort" system which moisturises the cabin air through evaporative cooling. The system received its first US order in November when it was selected by Texas-based completion specialist Associated Air Center for a VIP 767. The system takes water from the aircraft's water supply system to raise the relative humidity level in the cabin from the standard 5% to a more pleasant ambient 20-25% level.
Source: Flight International
