AN AIRCRAFT DE-ICING system in which infra-red (IR) heaters are used instead of environmentally damaging glycol-based fluids is ready to become operational at airports at Rheinlander, Wisconsin, and Rochester, New York.

A prototype, developed by Process Technologies of Cheektowaga, New York, has already been tested at Greater Buffalo International Airport, New York, under the supervision of the US Federal Aviation Administration. If funding can be found, Rheinlander and Rochester hope that the system, known as Infratek, will be installed in time for the North American winter.

"Clean-burning" propane is used to power the IR heaters, which are designed to reduce significantly the cost of de-icing an aircraft, compared with using conventional glycol sprays. De-icing 3mm (1/8in)-thick clear ice from the surface of a Boeing 737 can cost up to $3,500 and take 15-20min when using glycol: the Infratek is claimed to perform the same task for $110 in 15min.

Each Infratek installation includes an array of energy-process units (EPUs) set above the aircraft, which taxis into position. IR energy is an electromagnetic wave form released from a hot surface.

The wavelength of the IR energy released depends on the surface temperature of the emitter - the higher the temperature, the shorter the wavelength of the IR energy.

The EPUs are designed to provide maximum possible IR energy output via electromagnetic wave lengths, which are absorbed by the ice, which covers the surfaces of an aircraft without warming the aircraft structure or fuel.

Primary heat-exchange surfaces are heated to 1,092°C, releasing IR energy at around 75% efficiency. The electro-magnetic wave length of the IR energy, is then controlled by using a larger, secondary, heat-exchange surface.

To offer a suitable building to house the de-icing system, Process Technologies has formed an alliance with Ventura, California-based Clamshell Buildings.

The so-called Clam-shelter is constructed from a series of aluminum "arches" and PVC panels, is fully relocatable, and is designed to withstand wind speeds of 95kt (170km/h) and a snow load of 125kg/m2.

The largest buildings so far are 48m (160ft) wide and 17m high, but their modular design allows them to be built up to 300m long. According to Barry Sottak, vice-president of Clamshell Buildings, units some 85m wide and 25m high - capable of accommodating a Boeing 747 - will be available in six to nine months' time.

Source: Flight International