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Tuesday, August 27, 2013

Guest Blog : The Evolution of the Light Bulb

Now that the era of incandescent light is drawing to a close, if feels like an appropriate time to consider the history of electric domestic lighting. 

Here's a guest review article that has been submitted by Adam Stevens of Enviko specifically for Ban The Bulb about the evolution of the bulb.

Light bulbs have been a vital piece of technology which has been undervalued due to it's huge contribution to modern life. It was first concocted in 1850 by Joseph W. Swan who began working on a light bulb using carbonised paper filaments in that very same year.

Then in 1878 Thomas Edison, the person famous for the light bulb, founded the Edison Electric Light Company. The year after Swan began installing light bulbs in homes and landmarks in England.

After this breakthrough and homes were lit, ductile tungsten was invented. This made light bulbs a lot safer and brighter. The filament material started to be used as tungsten filament much like the modern incandescent light bulb. This was manufactured by the General Electric Company and William Coolidge in 1908.

As tungsten has a very high melting point it can be heated to 3000°C to achieve a white hot glow providing a level of brightness never seen before in a light bulb.

However, due to the high level of heat, these bulbs did not last as long as previous versions, therefore a fix was conjured up. This fix was to insert inert gasses such as nitrogen and argon into the light bulb to reduce tungsten evaporation or sublimation.

These gases did reduce evaporation and increase filament life, and they also carried heat away from the filament, which reduced its temperature and brightness. Again, a fix was needed. The boffins then came up with the idea to wind the wires into fine coils, again as they are in modern incandescent filaments. This reduced convective heat loss and allowed the filament to operate at the desired temperatures.

Nowadays, light bulbs have improved but are still not energy efficient. Only four to six per cent of the electrical power supplied to the bulb is converted into visible light. The other 94 per cent is lost as heat.

Although, these light bulbs are now being phased out in many countries they were attractive to consumers for the following reasons:

     Wide, low-cost availability
     Easy incorporation into electrical systems
     Adaptable for small systems
     Low voltage operation, such as in battery powered devices
     Wide shape and size availability

Compact Fluorescent Lamps are a lot more efficient than the outdated incandescent bulb as they give out the same amount of visible light while using only one-fifth to one-third of the electrical power, as well as lasting eight to fifteen times longer.

Due to their efficiency, the CFLs have a higher retail price but do save a considerable amount which will save you more than the retail price difference. They typically have a service life of 6,000 to 15,000 hours over the incandescent lights service life of 750 to 1,000 hours. And for LED lamps they can last up to 100,000 hours.

Europe has tried to implement a law that requires people to switch over from incandescent lamps. This was the EU guideline 244/2009 which will prohibit the production and import of less energy efficient light bulbs by 2012. The UK had already implemented a law much like this which has been working ahead of the EU law.

As a result of this standard filament bulbs from 60W upwards have now been phased out and lower output bulbs were also phased out in September 2012. Halogen spotlights will have to meet new minimum efficiency standards from 2016.

LED Lamps use 90% less electricity that old-fashioned incandescents and within the next few years are likely to take a massive portion of the lighting sector due to their dimmable capabilities, colour range and falling prices. 

What are your predictions for the future of light bulbs? Tell us via email