Friday, June 5, 2015

Fiat Lux

And God said, Let there be light: and there was light (Genesis 1:3)

and

Nature and Nature's laws lay hid in night: God said, Let Newton be! and all was light, an epitaph Isaac Newton's admirer Alexander Pope had formulated, but the church authorities did not allow it to be put on Newton's monument in Westminster Abbey.


In 2013, the UN General Assembly proclaimed 2015 as the International Year of Light and Light-based Technologies (IYL 2015). The aim is to raise awareness about how these technologies provide solutions to global challenges in energy, education, agriculture, and health.

Red Baron had prepared a blog about the IYL at the beginning of the year, but then he felt a serious plug needed to be included.

The plug came in today's Badische Zeitung with an article about replacing incandescent halogen spotlights with LED spotlights in Freiburg's museums.

They are late in doing so, for Red Baron had already changed the halogen spotlights in his apartment one year ago. This exchange was not without problems concerning the light output and stability of the LED spotlights. Low-price LEDs tend to flicker when connected to high current 12 volts DC power supplies intended for halogen spotlights. Better and more expensive brands of LED spotlights cure this phenomenon with built-in electronic circuits.

Two LED spotlights and a smoke detector
Due to the different light emission angles, always opt for replacements with a higher light output. A warm white (2700 K) halogen spotlight of 35 watts has an output of 350 lumens and a lifetime of 1500 hours. The recommended LED replacement with a 15,000-hour lifetime consumes only 6.8 watts for the same light output. Red Baron, however, considers that physiologically a warm white LED spotlight of 8 watts and 420 lumens is required to make you forget a 35 watts halogen spotlight.

Do not think you will make an immediate economy when replacing your "heating" spotlights with "cool" LEDs. First, you must consider the electrical power consumption, where you only pay about 10 cents per kilowatt hour in the States compared with Germany, where the price is double. Secondly, you replace your halogen spotlight ten times more often than the LED counterpart, with the latter being up to twenty times more expensive than the halogen light.

From the article in the BZ, Red Baron learned that there are other advantages of LED over halogen spotlights: The former emit no UV light and no heat. Both characteristics are essential when sensitive objects of art are illuminated. The replacement of halogen spotlights in Freiburg's museums will cost more than half a million euros leading to a yearly economy in the electricity bill of 30,000 euros. This covers the energy aspects of the IYL 2015.


Here is some cultural information about light. Goethe's famous last words on March 22, 1832, were: More light, more light. For more than 150 years, literary scholars have claimed that he had asked that the shutters in his darkened Sterbezimmer (the room where he died) be opened.

A modern, less romantic interpretation is that Goethe's brain becoming deprived of oxygen, answered with a release of endorphins, and the poet's mind had entered - what people who have survived their NDE (near-death experience) often described - the tunnel of light.
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