A first: The all-LED office building

Automation supplier IDEC Corp. got some attention last year when it finished outfitting one of its sales offices in Japan with LED illumination inside and out. The building is lit by 11,000 LED devices and 250,000 LED chips which handle the interior, parking lot, and garden.

IDEC designed and manufactured all the LEDs and fixtures. Recently IDEC explained to EE&T some of the challenges of the project. Getting heat out of the LED packages and fixtures was a key, engineers there say. They also say some of the structural elements they came up with to dissipate heat were ingenious. Fixtures included heat sinks and a housing design that promoted heat dispersion.

Effort also went into devising special constant-current power supplies able to drive the LED fixtures. The resulting supplies incorporate a modulation circuit that meters power demands depending on ambient light levels.

The LED fixtures are a one-for-one substitute for conventional fixtures. A single 600×600-mm LED fixture for dropped ceilings puts out the same brightness as a conventional 100-W fixture, IDEC says. But glare is more of a problem with LED fixtures, says IDEC. So the company incorporated light-shielding plates between LED modules angled with the line-of-sight to divert direct lighting. Diffusing acrylic panels also keep down glare.

Modules also incorporate LEDs alternating between two different color temperatures, white and warm white. This serves further reduce glare and create a natural color temperature.

Designers first simulated the illuminance to determine how the lights should be laid out, then measured real values to make sure targets were hit.

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