Lighting the Way to the Future with LED

Christmas is fast approaching and many of us will be buying new lights for decorations.  Read this earlier post below before you shop. LED lights may cost a little more up front but will save you with much longer lifetimes and lower energy usage.

With energy likely to be in short supply and expensive in the future due to unwise policy that is limiting the building of new power plants in deference to unreliable alternative energy sources, ways to save on energy will become increasingly important. Homes will be better insulated, cars and home appliances more energy efficient. The most used device we have in our homes is the light bulb. It is the last thing we turn out before we turn in. There are often multiple lights in each room and a typical home may have many running at once. Since it is so much in use, finding ways to save on the energy used in home lighting will pay big dividends. Let’s start by looking at the different types of bulbs used.

INCANDESCENT BULBS

It is widely regarded that Thomas Alva Edison invented the first reasonably practical incandescent lamp, using a carbon filament in a bulb containing a vacuum. Edison’s first successful test occurred in 1879. There were earlier incandescent lamps, such as one by Heinrich Goebel made with a carbon filament in 1854. This incandescent lamp had a carbonized bamboo filament and was mentioned as lasting up to 400 hours. Some sources regard Goebel as the inventor of the incandescent lamp. Since that time, the incandescent lamp has been improved by using tantalum and later tungsten filaments, which evaporate more slowly than carbon. Nowadays, incandescent lamps are still made with tungsten filaments. The filament of an incandescent lamp is simply a resistor. As electrical power is applied, it is converted to heat in the filament. The filament’s temperature is very high, generally over 3600 degrees Fahrenheit. In a “standard” 75 or 100 watt 120 volt bulb, the filament temperature is roughly 4600 degrees Fahrenheit. At high temperatures like this, the thermal radiationfrom the filament includes a significant amount of visible light.

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In a 120 volt, 100 watt “standard” bulb with a rated light output of 1750 lumens, the efficiency is 17.5 lumens per watt. This compares poorly to an “ideal” of 242.5 lumens per watt for one idealized type of white light, or 683 lumens per watt ideally for the yellowish-green wavelength of light that the human eye is most sensitive to.

FLOURESCENT BULBS

In 1857, the French physicist Alexandre E. Becquerel who had investigated the phenomena of fluorescence and phosphorescence, theorized about the building of fluorescent tubes similar to those made today. Alexandre Becquerel experimented with coating electric discharge tubes with luminescent materials, a process that was further developed in later fluorescent lamps.

American, Peter Cooper Hewitt (1861-1921) patented (U.S. patent 889,692) the first mercury vapor lamp in 1901. The low pressure mercury arc lamp of Peter Cooper Hewitt is the very first prototype of today’s modern fluorescent lights. A fluorescent light is a type of electric lamp that excites mercury vapor to create luminescence.

The Smithsonian Institute states that, “Electrical inventor, Peter Cooper Hewitt built on the mid-19th century work of German physicist Julius Plucker and glassblower Heinrich Geissler. By passing an electric current through a glass tube containing tiny amounts of a gas, Plucker and Geissler found they could make light. Peter Cooper Hewitt began developing mercury-filled tubes in the late 1890s, and found that they gave off an unappealing bluish-green light. The amount of light, however, was startling. Hewitt realized that few people would want his lamps in their homes, and so concentrated on developing a product for other uses.” That purpose turned out to be lighting for photographic studios and industrial use. George Westinghouse and Peter Cooper Hewitt formed the Westinghouse-controlled Cooper Hewitt Electric Company to produce the first commercial Mercury lamps.

Edmund Germer (1901 – 1987) invented a high pressure vapor lamp, his development of the improved fluorescent lamp and the high-pressure mercury-vapor lamp allowed for more economical lighting with less heat. Edmund Germer was born in Berlin, Germany, and educated at the University of Berlin, earning a doctorate in lighting technology. Together with Friedrich Meyer and Hans Spanner, Edmund Germer patented an experimental fluorescent lamp in 1927.

Edmund Germer is credited by some historians as being the inventor of the first true fluorescent lamp. However, it can be argued that fluorescent lamps have a long history of development prior to Germer. George Inman lead a group of General Electric scientists researching an improved and practical fluorescent lamp. Under pressure from many competing companies the team designed the first practical and viable fluorescent lamp (U.S. Patent No. 2,259,040) that was first sold in 1938. It should be noted that General Electric bought the patent rights to Edmund Germer’s earlier patent

According to The GE Fluorescent Lamp Pioneers, “On Oct 14, 1941 U.S. Patent No. 2,259,040 was issued to George E. Inman; the filing date was Apr 22, 1936. It has generally been regarded as the foundation patent. However, some companies were working on the lamp at the same time as GE and some individuals had already filed for patents. GE strengthened its position when it purchased a German patent that preceded Inman’s. GE paid $180,000 for U.S. Patent No 2,182,732 that had been issued to Friedrich Meyer, Hans J. Spanner and Edmund Germer. While one might argue the real inventor of the fluorescent lamp, it is clear that GE was the first to introduce it.”

You see fluorescent lighting everywhere these days — in offices, stores, warehouses, street corners… You’ll find fluorescent lamps in peoples’ homes under kitchen counters and in workshops. But even though they’re all around us, these devices are a total mystery to most people. Just what is going on inside those white tubes

The central element in a fluorescent lamp is a sealed glass tube. The tube contains a small bit of mercury and an inert gas, typically argon, kept under very low pressure. The tube also contains a phosphor powder, coated along the inside of the glass. The tube has two electrodes, one at each end, which are wired to an electrical circuit. The electrical circuit is hooked up to an alternating current (AC) supply.

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When you turn the lamp on, the current flows through the electrical circuit to the electrodes. There is a considerable voltage across the electrodes, so electrons will migrate through the gas from one end of the tube to the other. This energy changes some of the mercury in the tube from a liquid to a gas. As electrons and charged atoms move through the tube, some of them will collide with the gaseous mercury atoms. These collisions excite the atoms, bumping electrons up to higher energy levels. When the electrons return to their original energy level, they release light photons.

COMPACT FLOURESCENTS

Compact fluorescent lights, or CFLs, are constantly in the news due to their energy efficient qualities. Not only do these light bulbs utilize less energy, but they produce less heat helping to save energy in cooling costs and prolonging the life of the bulb.
Compact fluorescent bulbs produce light that’s more diffuse than incandescent bulbs, so they are very good for area lighting. Compact fluorescent bulbs use about one-quarter of the energy an incandescent bulb to produce the same amount of light. A good comparison ratio takes a 15-watt CFL to replace a traditional 60-watt bulb. The lower wattage equals less energy use and less heat output. Look for packages that provide conversions for consumers to get the best fitting bulb for your needs.

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CFLs can cause interference with devices such as radios and computers. In this event, move the lamp or the electronic devices away from each other. The start-up time of a compact fluorescent bulb can be slower than an incandescent bulb, even though the color and brightness are similar. Compact fluorescent bulbs contain trace amounts of mercury, so when they burn out they need to be disposed of properly to prevent environmental damage.

CFLs can cause interference with devices such as radios and computers. In this event, move the lamp or the electronic devices away from each other. The start-up time of a compact fluorescent bulb can be slower than an incandescent bulb, even though the color and brightness are similar. Compact fluorescent bulbs contain trace amounts of mercury, so when they burn out they need to be disposed of properly to prevent environmental damage.

LED BULBS

A light-emitting-diode (LED) is a light source that emits light when an electrical current is applied to it. Discovered in the early 20th century, the technology has been greatly developed and continues to advance through research and development. From early indicator lights with low light output–with only one available color–to today’s devices that emit visible, ultraviolet or infra red light, with very high brightness.

The technology behind LED is based on semiconductor technology, which is also the basis of modern computers. In the semiconductor diode, electrons are brought from a state of high energy to a state of low energy state and this energy difference is emitted in the form of light, the effect is called electroluminescence.

Specific colors are associated with specialized materials, that are constructed to have an energy gap corresponding to light with particular wavelength/color.

LEDs have many advantages to traditional light sources, such as: low energy consumption, longer lifetime, little heat production (thus loss), robustness, small size and others. However they still remain relatively expensive per unit cost. However, in the end they save considerable money and energy when you consider lifetime, energy used, efficiency and safety.

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If each U.S. household replaced just one standard 60 watt bulb with a CC Vivid LED Light bulb, the energy savings would be greater than the amount of energy produced by one of the largest power plants in the U.S..We could save 26,068,180,736 watts or 26,068 mega (million) watts per day.

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Palo Verde Nuclear Generating Station, located in Wintersberg, Arizona, is the largest nuclear generation facility in the U.S. is capable of producing over 3,875 megawatt of electricity.

ONE APPLICATION EXAMPLE – CHRISTMAS LIGHTING

Many homes are decorated with outdoor Christmas lights. Not too many years ago, most were incandescent bulbs not unlike those still found in most night lights. They were often C7 (7 watt) or C9 (9 watt) bulbs.

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In recent years, mini-lights became more popular for both outdoor and indoor applications as they use less electricity and run cooler, posing less of a fire hazard.

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LED Mini Lights are now becoming most popular. Super Bright LED Mini Christmas lights will last 100,000 hours and will cost 90% less to run that traditional Christmas lights. Because they have no filament, they require less energy, produce less heat, and last a great deal longer. Because the LED’s energy is not being wasted heating a filament and a greater percentage of power is going directly to generate light, making them much brighter than traditional bulbs. Furthermore, the bulb is constructed out of heavy plastic and therefore remarkably durable.

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Despite the fact they tend to cost more than traditional mini or C7 strings, the single season and long term cost savings are impressive

EXAMPLE:
A home decorated with 2400 lights outdoors that are run for 45 days at 6 hours per day at a cost of electricity of $0.10/kilowatt hour.
C7 bulbs: $324.00
Mini-lights: $26.44
LED mini-lights: $5.20

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One thought on “Lighting the Way to the Future with LED

  1. Pingback: Savings Experiment: Which lightbulbs save the most money? «

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