Ivica Kolaric of the Fraunhofer Technology Development Group TEG in Stuttgart, Germany, has developed a new process for warming windscreens and thus preventing condensation forming on cold days. Rather than copper heating elements, the technique uses a transparent coat of carbon lacquer, formed of carbon nanotubes.
Kolaric and colleagues are now working on a bonding system for applying the coating that would be suitable for use on bathroom mirrors also.
When attached to an electricity supply, the lacquer coating is transformed into a wide, flat heater, which completely covers the surface to be heated and continues to function even if it is damaged. If a heated windshield containing wire heating elements is damaged so that one of the wires is severed, the entire heater may cease to function because the current is interrupted.
But a few small defects in the carbon nanotube coating are not a problem because the current flows over the whole surface. A further advantage of the flat conductor is its uniform heat distribution. Every single point on the surface of the windshield is heated evenly, rather than the warmth radiating outwards from the heating elements.
The coating does not store any heat. “The lacquer converts the electricity almost entirely into warmth and transfers this to the windscreen,” explains Kolaric. The glass is clear in a very short time with minimal power consumption. The carbon nanotube resistance heater can be integrated in a vehicle’s standard 12-volt power supply.