Temperatures rises for LED thermometer

May 25, 2006
A Spanish firm has exploited LED technology to build a huge thermometer on the side of a building in Madrid.
Semai Lighting of Spain has used more than 3200 high-power LEDs to build a 30 m high thermometer on the side of the Gas Natural corporate office building in Madrid.

The new installation replaces an earlier version that relied on 50 W halogen lamps, and is expected to lower energy consumption by more than 85% as well as making considerable savings on maintenance costs.

Each degree Celsius in the thermometer consists of a module measuring 3030 cm, and a total of 80 modules were installed on the side of the building to form the thermometer.

Each module incorporates 40 high-power LEDs, which are fitted with collimator optics that produce light emission over an angle of 40°. Individual modules consume 51 W of power and produce a luminous flux of 2040 lm at a wavelength of 617 nm.

An electrical circuit exploiting pulse-width modulation allows the intensity of light output to be varied. Two different luminance values available during the day, and the light output is reduced by 30% at night.