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July 26, 2009 @ 6:16 pm
From BC to T.A.E. to LEDs, Part 2

After the magic lantern in Part 1, history’s lighting developers refocused their collective effort on lamps. In fact, I could go on and on about incremental lamp technologies but that would be boring so here’s a quick timeline with major developments:

  • Argand Lamp – First major new lamp technology in millennia, this 1780’s oil lamp used a hollow circular wick surrounded by a glass chimney (better combustion, brighter light, less smoke)
  • Betty Lamp – 1790, a metal variation of Greek/Roman pottery lamps with a wick support that directed the oil drip back into the reservoir, thus it was a “better lamp” and the Betty Lamp colloquialism was born
  • Electric Arc Light – 1800’s, electric candles whereby two parallel sticks of carbon were separated by an insulator whose slowly melting arch self fed the two carbons
  • Gas Lighting – 1800’s, lamps fueled by gas lines with valves to control the lighting circuits
  • Kerosene Lamp – 1853, this new fuel source was introduced in Germany and you have a cabin the woods somewhere you might even own a kerosene lamp or two today

After hundreds of theaters and who knows what else were burned down by gas lighting and other inferior technologies, Edison finally came along. He demonstrated his carbonized cotton filament based incandescent light bulb to the public on New Year’s Eve 1879. His bulbs were revolutionary, offering 16 candlepower, rated at 100 watts (only about 2 lumens per watt) and lasted for 100 hours. The stock price of Edison Electric Company quickly climbed, peaking at $3,500 per share! The simple lightbulb spawned a new industry; electric utilities, and there were 300 of these power stations by 1883.

During the 19th and 20th Century lots of incremental design improvements and updates to existing technologies with a particular emphasis on reduced wattage and energy savings came along. These designs utilized all manner of gases, filaments, etc. and are too numerous to mention – a helpful list is available from GE here. I promised to take us up to LEDs and the current marketplace so keep reading and enjoy the LED video!

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The forerunner of the compact fluorescent (developed in the late 1980’s) pictured above, fluorescent tubes were first sold commercially in 1938 and represented a major step toward greener, more energy efficient lighting. They utilize ultraviolet radiation inside the bulb to light up fluorescent powders and current models generate about 65-80 lumens per watt (up to 40 times the efficiency of Edison’s incandescent bulbs). In 1949, the soft white incandescent bulbs that are virtually glare-free and ubiquitous today were introduced – they now generate about 10-20 lumens per watt.

Initially invented in 1955, fiber optics ultimately revolutionized communications technology, making the limitless availability of information on the internet possible. The cables are not subject to interference like copper wiring is and information can be transmitted via light pulses at, you guessed it, the speed of light (approximately 186,000 miles/second or 299,000 km/second).

And now, the star of the show: light-emitting-diodes (LEDs). You may not realize it but you probably have many of these in your home and/or car. They were first developed in 1920’s Russia and were harnessed for practical applications by GE in 1962. They have been used in indicator lights for electronics virtually ever since. This was a perfect application because single LED is an individual semiconductor diode of less than 1 mm2 whose switch allows electrons to emit light (different semiconductors produce different colors). LEDs uniquely provide incredible power efficiency and extra long life. To conserve more energy and have truly green buildings and homes, they are the wave of the future. A 13 watt LED lamp is at least equivalent to a standard 40 watt incandescent bulb and can last more than 50 times longer. The resulting lumens per watt advantage means that a building’s carbon footprint from lighting can be reduced by 68% by exchanging all incandescent bulbs for new LEDs. Meanwhile, LED efficiency continues to increase, a prototype built by Cree achieved 161 lumens per watt in 2008. For information about buying LED strips, click here. As an added benefit, LEDs are non-toxic whereas fluorescents and compact fluorescents (CFLs) contain harmful mercury.

For reference sake, the standard fluorescent tubes and incandescent bulbs that are probably lighting your office or home right now are rated at 10,000 to 15,000 hours and 1,000–2,000 hours, respectively (see above for lumens per watt). If you’ve already switched your home lighting to CFLs, that’s great news – you’ll be getting 6,000 and 15,000 hours of use (over 6 times incandescent lifespan) and 60-72 lumens per watt (up to 7 times the efficiency of incandescents). Translation: net $ savings on electricity despite the higher upfront cost of CFLs.

Check out this video of the “Zero Energy Media Wall” in Beijing. It is made of LEDs fully powered by integrated solar cells.

Finally, what would a post on lighting be without a light bulb joke? Since I do some consulting work, here’s one I found on a “History of Light” website I referenced for these posts on lighting:

Q: How many consultants does it take to change a light bulb?
A: I’ll have an estimate for you a week from Monday.

3 Responses to “From BC to T.A.E. to LEDs, Part 2”

  1. GreenBldgBlog - Home Says:

    […] projection device and ultimately the first step on a path toward motion pictures. Check out Part 2 here! Filed under Electricity, Energy Efficiency, Lighting […]

  2. GreenBldgBlog - Home Says:

    […] you read my post on the history of lighting (Part 1 and Part 2) then you know about the energy efficiency benefits of LEDs as a light source. Ricoh, the office […]

  3. GreenBldgBlog - Home Says:

    […] from Treehugger features several, including the Zero Energy Media Wall from my recent lighting post as well as one of the Olympics building complexes (the athlete’s village). Now, I’ll focus on […]

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