Friday, June 5, 2015

Fiat Lux

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


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 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 that a serious plug was missing.

In today's Badische Zeitung I read an article about the replacement of incandescent halogen spotlights with LED spotlights in Freiburg's museums. They are late in doing so for Red Baron had changed the halogen spotlights in his apartment already one year ago. This exchange was not without problems with respect to 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 angles of light emission always opt for replacements with a higher light output. A warm white (2700 K) halogen spotlight of 35 watts has an output of 350 lumen 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 lumen is required to make you forget a 35 watts halogen spotlight.

Do not think that 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 cent 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 but 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 important 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 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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